The correct option is C Ecdysone
Metamorphosis is controlled by ecdysone hormone which is a prothoracicotropic hormone. It is secreted by the prothoracic gland and triggers moulting. It activates tissue to promote metamorphosis. Pheromone is a chemical in animals produces which changes the behaviour of another animal of same species while thyroxine helps in the metamorphosis in frogs.
So, the correct answer is option C.