The correct answer is **B) 575 units**.\n\nLet's systematically fill the table using the given information and principles of arithmetic consistency (vertical and horizontal totals).\n\n**Step 1: Identify and record initial known values.**\n\n* Grand Total Sales = 1500 units (Given in the table).\n* Sales of Product A in Q1 (A_Q1) = 120 units (Clue 1).\n* Sales of Product B in Q2 (B_Q2) = 200 units (Given in the table).\n* Sales of Product C in Q3 (C_Q3) = 150 units (Given in the table).\n* Total Sales in Q2 (Total_Q2) = 600 units (Given in the table).\n\n**Initial Table State:**\n\n| Product | Q1 | Q2 | Q3 | Total Sales (Product) |\n| :------ | :-- | :-- | :-- | :-------------------- |\ | A | 120 | | | |\n| B | | 200 | | |\n| C | | | 150 | |\ | **Total (Quarter)** | | 600 | | **1500** |\n\n**Step 2: Calculate Sales of Product B in Q1 (B_Q1).**\n\n* From Clue 2: Sales of Product B in Q1 are 25% more than sales of Product A in Q1.\n* \\(B_{Q1} = A_{Q1} \\times (1 + 0.25) = 120 \\times 1.25 = 150\\) units.\n\n**Step 3: Calculate Total Sales of Product A (Total_A).**\n\n* From Clue 4: Total sales of Product A is 30% of the Grand Total sales.\n* \\(Total_A = 0.30 \\times 1500 = 450\\) units.\n\n**Step 4: Calculate Total Sales for Q1 (Total_Q1) and Q3 (Total_Q3).**\n\n* The sum of total sales for all quarters must equal the Grand Total:\n \\(Total_{Q1} + Total_{Q2} + Total_{Q3} = Grand\\ Total\\)\n \\(Total_{Q1} + 600 + Total_{Q3} = 1500\\)\n \\(Total_{Q1} + Total_{Q3} = 1500 - 600 = 900\\) units.\n* From Clue 5: The ratio of total sales of Q1 to Q3 is \\(4:5\\).\n* \\(Total_{Q1} = \\frac{4}{4+5} \\times 900 = \\frac{4}{9} \\times 900 = 4 \\times 100 = 400\\) units.\n* \\(Total_{Q3} = \\frac{5}{4+5} \\times 900 = \\frac{5}{9} \\times 900 = 5 \\times 100 = 500\\) units.\n\n**Updated Table State:**\n\n| Product | Q1 | Q2 | Q3 | Total Sales (Product) |\n| :------ | :-- | :-- | :-- | :-------------------- |\ | A | 120 | | | 450 |\n| B | 150 | 200 | | |\n| C | | | 150 | |\ | **Total (Quarter)** | 400 | 600 | 500 | **1500** |\n\n**Step 5: Calculate Sales of Product C in Q1 (C_Q1).**\n\n* The sum of product sales in Q1 must equal Total_Q1:\n \\(A_{Q1} + B_{Q1} + C_{Q1} = Total_{Q1}\\)\n \\(120 + 150 + C_{Q1} = 400\\)\n \\(270 + C_{Q1} = 400\\)\n \\(C_{Q1} = 400 - 270 = 130\\) units.\n\n**Step 6: Calculate Sales of Product C in Q2 (C_Q2).**\n\n* From Clue 3: Sales of Product C in Q2 are 1.5 times the sales of Product C in Q1.\n* \\(C_{Q2} = 1.5 \\times C_{Q1} = 1.5 \\times 130 = 195\\) units.\n\n**Step 7: Calculate Sales of Product A in Q2 (A_Q2).**\n\n* The sum of product sales in Q2 must equal Total_Q2:\n \\(A_{Q2} + B_{Q2} + C_{Q2} = Total_{Q2}\\)\n \\(A_{Q2} + 200 + 195 = 600\\)\n \\(A_{Q2} + 395 = 600\\)\n \\(A_{Q2} = 600 - 395 = 205\\) units.\n\n**Step 8: Calculate Sales of Product A in Q3 (A_Q3).**\n\n* The sum of sales of Product A across all quarters must equal Total_A:\n \\(A_{Q1} + A_{Q2} + A_{Q3} = Total_A\\)\n \\(120 + 205 + A_{Q3} = 450\\)\n \\(325 + A_{Q3} = 450\\)\n \\(A_{Q3} = 450 - 325 = 125\\) units.\n\n**Updated Table State (almost complete):**\n\n| Product | Q1 | Q2 | Q3 | Total Sales (Product) |\n| :------ | :-- | :-- | :-- | :-------------------- |\ | A | 120 | 205 | 125 | 450 |\n| B | 150 | 200 | | |\n| C | 130 | 195 | 150 | |\ | **Total (Quarter)** | 400 | 600 | 500 | **1500** |\n\n**Step 9: Calculate Sales of Product B in Q3 (B_Q3).**\n\n* The sum of product sales in Q3 must equal Total_Q3:\n \\(A_{Q3} + B_{Q3} + C_{Q3} = Total_{Q3}\\)\n \\(125 + B_{Q3} + 150 = 500\\)\n \\(275 + B_{Q3} = 500\\)\n \\(B_{Q3} = 500 - 275 = 225\\) units.\n\n**Step 10: Calculate Total Sales of Product B (Total_B).**\n\n* The total sales of Product B across all quarters is the sum of its sales in Q1, Q2, and Q3:\n \\(Total_B = B_{Q1} + B_{Q2} + B_{Q3}\\)\n \\(Total_B = 150 + 200 + 225 = 575\\) units.\n\nThus, the total sales of Product B across all quarters is 575 units.