Use the right form of the verb:

'Where ___ (Martin/come) from?' 'He's Scottish.'

In the sentence, "'Where does Martin come from?' 'He's Scottish,'" the present simple tense is used to ask about Martin's place of origin. The correct form for the sentence is "Where does Martin come from?"

The other options are not suitable because they do not use the correct verb form or tense:

Option A: do Martin come
This option combines the present simple tense "do" with the base form "come," which is not grammatically correct.

Option B: do Martin comes
This option combines the present simple tense "do" with the present simple third-person singular form "comes," which is not appropriate for the question.

Option C: does Martin comes
This option uses the present simple tense "does" with the present simple third-person singular form "comes," which is also not appropriate for the question.

Therefore, the correct answer is Option D: does Martin come.