Option A - 'He' is a third person pronoun. Thus option A is incorrect.
Option B - 'Is' is an auxiliary which is used with a singular subject in the present tense. Thus option B is incorrect.
Option D - 'Eating' is the participle form of the verb. Thus option D is incorrect.
Option C - 'Of' explains possession/beginning/origin. It is a preposition. Thus option C is the correct answer.