Read the following sentence from the middle of the article.
They numbered 700 in all, and the many conveniences of the mammoth structure for facilitating
the work of landing were made manifest by the rapidity with which this number was registered
and sent on to their various destinations.
Which of the following is meant by the phrase "made manifest" in this sentence?
(A)
resolved
(B)
imagined
(C)
revealed
caught up
(D)