In each of the following sentences there is one... - SS1 English Vocabulary Development : Antonyms exactly opposite in meaning. Question

In each of the following sentences, there is one underlined word and one gap. from the list of words lettered A to D, choose the one that is most nearly opposite in meaning to the underlined word and that will, at the same time, correctly fill the gap in the sentence  (waec 2015).

Young people are known for their....which contrast with the composure of adults.