Concept:The structure “two of his” requires a simple plural noun to refer to a group of people.Explanation:The expression “two of his _____” means two persons selected from among his friends.Therefore, the missing word must be the ordinary plural form “friends”.An apostrophe is not needed because the sentence does not show possession.The forms “friend’s” and “friends’” are possessive, and “friend” is singular, so they do not fit correctly.Answer:A. friends