Expense on fuel consumption as a percentage of input cost has been HIGHEST for

Let's solve the options one by one.

Option A: For industry 3:

Fuel consumed  = 10817 lakhs

Total inputs cost = 80238 lakhs.

Required ratio = $$\ \frac{\ 10817}{80238}$$ *100

= 13.48 %

Option B: For industry 7:

Fuel consumed = 32178 lakhs

Total inputs cost = 171246 lakhs.

Required ratio = $$\ \frac{\ 32178}{171246}$$ *100

= 18.79 %

Option C: For industry 2:

Fuel consumed = 762 lakhs

Total inputs cost = 5990 lakhs.

Required ratio = $$\ \frac{\ 762}{5990}$$ *100

= 12.72 %

Option D: For industry 6:

Fuel consumed = 6461 lakhs

Total inputs cost = 138780 lakhs.

Required ratio = $$\ \frac{\ 6461}{138780}$$ *100

= 4.6 %

Clearly B is the correct answer.