In a railway track, two rails are joined end to end with a gap in between them because A. Steel can be saved B. Accidents due to contraction in winter can be avoided C. Air-gaps are necessary for bearing the weight of running train D. Accidents due to expansion in summer can be avoided

The correct answer is: Accidents due to expansion in summer can be avoided.

The gap between two rails is called a “rail joint.” Rail joints are necessary to allow for the expansion and contraction of the rails due to changes in temperature. In the summer, the rails expand due to the heat, and in the winter, they contract due to the cold. If the rails were not joined with gaps, they would buckle and cause accidents.

The other options are

incorrect. Option A is incorrect because the amount of steel used in a railway track is not significantly affected by the presence or absence of rail joints. Option B is incorrect because accidents due to contraction in winter are not a major concern. Option C is incorrect because air-gaps are not necessary for bearing the weight of a running train.