مَنْ أَضْرِبُ؟ — زَيْدًا
Translation: Whom should I strike? — Zayd.
مَنْ: interrogative in the accusative position of object.
أَضْرِبُ: indicative present verb, implied “I” subject.
زَيْدًا: accusative object governed by an omitted imperative “Strike Zayd”.
Ellipsis is licensed by the understood question, not by arbitrary deletion in any sentence.