The proposal to lay a telegraph cable from Europe to America made oceanographic studies take on a(n) ______.

A．the American Navy
B．some early intercontinental travelers
C．those who earned a living from the sea
D．the company which proposed to lay an undersea cable

A．learn something while keeping something of its own
B．remain what they used to be
C．change itself as more, as it can
D．be careful in order not to be cheated