The correct answer is B. 783.
A composite sleeper is a type of railway sleeper made from a combination of wood and concrete. It is used in track construction to support the rails and distribute the weight of the train evenly. The minimum composite sleeper index prescribed on Indian Railways for a track sleeper is 783. This means that the sleeper must be able to withstand a load of at least 783 kN before it fails.
The other options are incorrect because they do not meet the minimum composite sleeper index prescribed on Indian Railways. Option A, 552, is too low. Option C, 1352, is too high. Option D, 1455, is also too high.
The minimum composite sleeper index is determined by a number of factors, including the type of track, the weight of the train, and the climate. The minimum composite sleeper index for a track sleeper in India is 783. This means that the sleeper must be able to withstand a load of at least 783 kN before it fails.