Answer:
C) will come
Explanation:
My father is in Japan now, but he <u>will come</u> in a month.
C. Will come
if it's happening in a month and he's currently in Japan, then you'd use future tense. he WILL COME in a month. it can't be came or come, those don't make sense. can't be D either, "will" what? it doesn't make sense grammatically.
A. Excluded
Citizens and knowledge
C is the best answer, if you read it out loud it is the smoothest sounding