Percentage of in operative cylinders that can be attached in goods train is A. 15% B. 10% C. 5% D. None of these

The correct answer is D. None of these.

The percentage of inoperative cylinders that can be attached in a goods train is 0%. This is because the Indian Railways has a strict policy of not allowing any inoperative cylinders to be attached to goods trains. This policy is in place to ensure the safety of passengers and goods.

Option A is incorrect because it is more than the permissible limit of 0%. Option B is incorrect because it is less than the permissible limit of 0%. Option C is incorrect because it is not a valid option.