Explanation
Correct answer: A.
Choice A is the best answer. “That is…field” is an essential supplement, so we should not use punctuation to separate it from “scuba diving club.” .
Why the other choices are wrong
Choice B
Choice B is incorrect. This choice creates a punctuation error. “That is…field” is an essential supplement, so we should not use a comma (or any kind of punctuation) to separate it from “scuba diving club.” .
Choice C
Choice C is incorrect. This choice creates a punctuation error. “That is…field” is an essential supplement, so we should not use a dash (or any kind of punctuation) to separate it from “scuba diving club.” .
Choice D
Choice D is incorrect. This choice creates a run-on sentence. It makes “that is…United States” into an awkward independent clause, but it also makes “that has…field” into its own awkward independent clause without the correct punctuation separating it.