The proposal to lay a telegraph cable from Europe to America made oceanographic studies take on______.

A．the beginnings of oceanography
B．the laying of the first undersea cable
C．the investigation of ocean depths
D．the early intercontinental communications

A．to make some sounding experiments in the oceans
B．to collect samples of sea plants and animals
C．to estimate the length of cable that was needed
D．to measure the depth of the two oceans