when my parents-----for a visit tomorrow,they will see our new baby of the fist time.                                                                                                  A.will arrive      B.arrives           C.will have arrived     D.arrived

Option C. will have arrived and Option D. arrived are also incorrect as they do not fit the future tense context of the sentence.

Option B. arrives is incorrect because we need to use the future tense 'will arrive' as the action is planned for the future.

When my parents will arrive for a visit tomorrow, they will see our new baby for the first time.

The correct answer is A. will arrive.