Correct option is C
The correct active form is (c) "May God bless you with good health."
The original sentence, "May you be blessed with good health," is an expression of a wish or hope in passive voice.
The active form of this wish would directly invoke the agent doing the blessing, which in many cultural and religious contexts, is typically God.
Thus, "May God bless you with good health" is the most appropriate active voice transformation of this sentence.