As the divers went down to the ocean floor, the telephone __________.
A.kept working all the time
B.stopped working at a depth of 3, 000 feet and began working again after they reached the bottom
C.stopped working at a depth of 3, 000 feet and began working again at 30, 000 feet
D.stopped working at a depth of 3, 000 feet and began working again when they returned t the same depth