18
19
20
21
Answer is Right!
Answer is Wrong!
The correct answer is C. 20.
A broad gauge route with M+7 sleeper density has 20 sleepers per rail length. This means that there are 20 sleepers for every 1 meter of rail. The M+7 sleeper density is a standard sleeper density used in India. It is a relatively high sleeper density, which helps to distribute the weight of the train more evenly and provides a more stable track.
The other options are incorrect because they do not represent the correct number of sleepers per rail length for a broad gauge route with M+7 sleeper density. Option A, 18 sleepers per rail length, is too low. Option B, 19 sleepers per rail length, is too high. Option D, 21 sleepers per rail length, is also too high.
I hope this helps!