The question reads:

In which of the following situations can freezing rain be encountered ?

(a) Ahead of a cold front in the winter

(b) Ahead of a warm front in the winter

(c) Behind a warm front in the summer

(d) Ahead of a cold front in the summer

Freezing rain is encountered ahead of a warm front or behind a cold front. - Ahead of the warm front where the freezing level in the cold air is lower than the freezing level in the warm air above it.