Explanation
Correct answer: B.
Choice B is the best answer. “Marie tharp” is essential information that completes the first clause — the first clause doesn’t function without it. So we don’t want to separate it with punctuation.
Why the other choices are wrong
Choice A
Choice A is incorrect. This choice creates a punctuation error. “The field of geological oceanography owes much to American geologist” is unclear: which geologist are we talking about? We need the “Marie Tharp” for clarity, which means it’s essential information and should not be separated by a comma.
Choice C
Choice C is incorrect. This choice creates a punctuation error. “The field of geological oceanography owes much to American geologist” is unclear: which geologist are we talking about? We need the “Marie Tharp” for clarity, which means it’s essential information and should not be separated by a semicolon.
Choice D
Choice D is incorrect. This choice creates a punctuation error. “The field of geological oceanography owes much to American geologist” is unclear: which geologist are we talking about? We need the “Marie Tharp” for clarity, which means it’s essential information and should not be separated by a colon.