A bookseller sold 'a' number of Geography textbooks at the rate of Rs. x per book, 'a + 2' number of History textbooks at the rate of Rs. (x + 2) per book and 'a - 2' number of Mathematics textbooks at the rate of Rs. (x - 2) per book. What is his total sale in Rs.?

The total sale is the sum of sales from each type of textbook.

1. Sale from Geography textbooks: Number of books = a Rate per book = Rs. x Sale = a * x = ax

2. Sale from History textbooks: Number of books = a + 2 Rate per book = Rs. (x + 2) Sale = (a + 2) * (x + 2) = ax + 2a + 2x + 4

3. Sale from Mathematics textbooks: Number of books = a - 2 Rate per book = Rs. (x - 2) Sale = (a - 2) * (x - 2) = ax - 2a - 2x + 4

Total Sale = (ax) + (ax + 2a + 2x + 4) + (ax - 2a - 2x + 4)

Combine like terms: ax + ax + ax = 3ax +2a - 2a = 0 +2x - 2x = 0 +4 + 4 = 8

Total Sale = 3ax + 0 + 0 + 8 = 3ax + 8

Analyzing the options: A) 3x + 3a: This is incorrect. It does not account for the product 'ax' or the constant term '8'. B) 3ax + 8: This matches our calculated total sale. C) 9ax: This is incorrect. It would imply a different calculation, for example, if the terms were multiplied incorrectly. D) x³ a³: This is incorrect. It represents a cubic product, which is not derived from the given linear expressions.

The final answer is 3ax + 8.

The correct answer is B.