Correct Answer: (a) trumpet
Solution:'Trumpet' will be used in the blank space as the context of the blank is a sound resembling that of a trumpet, especially the loud cry of an elephant.
Trumpet: a brass musical instrument with a flared bell and a bright, penetrating tone. The modern instrument has the tubing looped to form a straight-sided coil, with three valves.
Frolic: play or move about in a cheerful and lively way.
Whine: a long, high-pitched complaining cry.10
Sing: make musical sounds with the voice, especially words with a set tune.
Hence, A is the right answer choice.