Select the most appropriate option to fill in the blank and make a grammatically correct sentence.

Chris and I play tennis together regularly, but ________ of us can play very well.

neither

The most appropriate option to fill in the blank is neither.

The sentence is saying that neither Chris nor the speaker can play tennis very well. The word "neither" is used to indicate that two things are not the same or do not have the same quality. In this case, Chris and the speaker are not the same in terms of their tennis skills.

The other options are not as appropriate.

• Both is used to indicate that two things are the same or have the same quality. It does not make sense in this context, because Chris and the speaker are not the same in terms of their tennis skills.
• Either is used to indicate that one of two things is possible. It does not make sense in this context, because the speaker is saying that neither Chris nor the speaker can play tennis very well.
• None is used to indicate that there is not any of something. It does not make sense in this context, because Chris and the speaker are two people.