PT 63 S4 Q16

Which one of the following most accurately expresses the main idea of the ... ...

Which one of the following most accurately expresses the main idea of the passage?
(A) In the 1950s, scientists refined their theories concerning the process by which the ocean floor was formed many millions of years ago.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in June 2011 LSAT (PT 63): Reading Comprehension