Explanation
Correct answer: D.
Choice D is the best answer. The convention being tested is the use of verb forms in a sentence. The plural verb “determine” supplies the main clause with a finite main verb and agrees in number with the plural subject “a state’s voting record and polling data.”
Why the other choices are wrong
Choice A
Choice A is incorrect because the singular verb “determines” doesn’t agree in number with the plural subject “a state’s voting record and polling data.”
Choice B
Choice B is incorrect because it results in an ungrammatical sentence. The nonfinite participle “determining” doesn’t supply the main clause with a finite plural verb.
Choice C
Choice C is incorrect because the singular verb “has determined” doesn’t agree in number with the plural subject “a state’s voting record and polling data.”