Has the students finished all their assignments yet?

Correct answer: A. Has

The subject "students" is plural, so it should be "Have" instead of "Has."

Their children have never were out of their village before.

Correct answer: B. were

The correct verb form is "been" instead of "were" for present perfect tense: "have never been."

She has not cooking for herself before, so she is not sure about what to do first.

Correct answer: B. cooking

The correct form is "cooked" (the past participle of "cook"). It should be "has not cooked."

Has he ever went scuba diving in the Caribbean?

Correct answer: B. went

The correct form is "gone" in the present perfect tense: "Has he ever gone scuba diving?"