What is the difference between the numbers of boys enrolled in C and the number of girls enrolled in E?

We know that the ratio of the total number of Boys to Girls ratio is 7:5;
we also know that the total number of students is 2400.
Taking Boys and Girls to be 7x and 5x respectively, we get 12x = 2400, giving us x = 200
And hence, the total number of boys to be 1400 and the total number of girls to be 1000. 

Next we're given that 15% of the boys are in section A, $$\frac{15}{100}\times\ 1400=210$$
And 22% of the girls are in section B, $$\frac{22}{100}\times\ 1000=220$$

Next, $$\frac{2}{7}$$ of the boys are in section B, $$\frac{2}{7}\times\ 1400\ =\ 400$$

We are also given that 500 boys are split between D and E in the ratio of 2:3, which would mean that D has 200 boys and E has 300 boys. 
And the remaining boys are in Section C; the number of boys remaining are 290. 

Next, we are given that 26% of the girls are in section D, that would mean that section d has 260 girls. 
We are also given that section B has 120 girls. 

The remaining girls must be split between section C and E, of which we know that C has 100 girls more than section E. 
Taking the number of girls in section E to be x, we can calulculate these values as we know that 400 girls are yet to be place in any section, 
giving us the equation $$2x+100=400$$
or simply $$x=150$$
which means that section E has 150 girls and Section C has 250 girls. 

Our final data looks like this:
Section       Boys    Girls
A                 210      220
B                 400      120
C                 290      250
D                 200      260
E                 300      150

The difference between the boys enrolled in C and girls enrolled in Section E is
=$$290-150$$
= 140

Hence, Option B is the correct answer.