Q: In the US, a primary election is a method -------- voters select the nominees for public office
A: that
B: is that
C: by which
D: by those
I am stuck between A and C
I agree with user178049 because method indicates "a means by which" something is achieved. "through which" is another possibility that might not sound as stilted.
However, you could revise the sentence as follows to eliminate the problem altogether: "Voters in the US select the nominees for public office in a primary election."
Conciseness in writing is important. The original would have had 18 words; the revision has 14.
The only correct answer is C. None of the other options fits.
Alternatively, the sentence would have to be amended:
In the US, a primary election is a method THAT voters USE TO select the nominees for public office
or
In the US, a primary election is a method THAT IS USED BY voters TO select the nominees for public office
or
In the US, a primary election is a method USED BY THOSE voters WHO select the nominees for public office