To solve this problem, we can use the principle of inclusion-exclusion. Let's break down the given information:

- 72% of the students took Biology, which means that 72% of the total number of students took Biology.
- 44% of the students took Mathematics, which means that 44% of the total number of students took Mathematics.
- 40 students took both Biology and Mathematics.

To find the total number of students in the class, we need to determine the number of students who took only Biology, the number of students who took only Mathematics, and the number of students who took both.

Let's assume the total number of students in the class is "x".

Number of students who took only Biology = 72% of x - 40 (students who took both)
Number of students who took only Mathematics = 44% of x - 40 (students who took both)

Now, we can find the total number of students in the class by adding the number of students who took only Biology, the number of students who took only Mathematics, and the number of students who took both:

Total number of students in the class = Number of students who took only Biology + Number of students who took only Mathematics + Number of students who took both

Total number of students in the class = (72% of x - 40) + (44% of x - 40) + 40

Simplifying the equation:

Total number of students in the class = 72% of x + 44% of x - 80 + 40

Total number of students in the class = 116% of x - 40

Now, we know that the total number of students in the class cannot be negative, so we can set up the following inequality:

116% of x - 40 > 0

Simplifying the inequality:

1.16x - 40 > 0

1.16x > 40

x > 40 / 1.16

x > 34.48

Since the number of students must be a whole number, the minimum value for x is 35.

Therefore, the total number of students in the class is at least 35.

Since the answer choices are given in whole numbers, we can check each option:

- For option A) 200, it is not feasible because it is much larger than the minimum value we found.

- For option B) 240, it is also not feasible because it is larger than the minimum value we found.

- For option C) 250, it is feasible because it is just slightly larger than the minimum value we found.

- For option D) 320, it is not feasible because it is much larger than the minimum value we found.

Therefore, the correct answer is option C) 250, as it satisfies the given conditions.