**Answer:**

Option B

**Explanation:**

For each subject, we find the overall percentage as under:

(l) Maths = $\frac{1}{7}$ × (90 + 100 + 90 + 80+ 80 +70+ 65)

= $\frac{1}{7}$ × 575 % = 82.14%

(ll) Chemistry = $\frac{1}{7}$ × (50+ 80 + 60 + 65 + 65 +75 + 35)

= $\frac{1}{7}$ × 430 % = 61.43%

(lll) Physics = $\frac{1}{7}$ × (90 + 80 + 70 + 80 + 85 + 65 + 50)

= $\frac{1}{7}$ × 520 % = 74.29%

(iv) Geography = $\frac{1}{7}$ × (60 + 40 + 70 + 80+ 95 + 85 +77)

= $\frac{1}{7}$ × 507 % = 72.43%

(v)History = $\frac{1}{7}$ × (70 +80+90+60+ 60+ 50 + 40 +80)

= $\frac{1}{7}$ × 470 % = 67.14%

(vl) Computer Science = $\frac{1}{7}$ × (80+70 +70 + 60 +90 +60+ 80)

= $\frac{1}{7}$ × 510 % = 72.86%.

Clearly, this percentage is highest for Maths.