In each of the following sentences there is one... - WAEC English 2003 Question

In each of the following sentences, there is one word underlined and one gap. From the list of words lettered A - D, choose the word that is most nearly opposite in meaning to the underlined word and that will, at the same time, correctly fill the gap in the sentences.
The testimony of the witness was so vague that it was difficult to learn the...........details of the case