Answer:
The correct answer is option D. ethylene.
Explanation:
Ethylene is a simple complex plant hormone and is created or produced by all organs. Ethylene is a gaseous hormone. It is transported through the spaces between cells of plants. It is responsible for fruits ripening, and causing abscission or leaves to be shed.
Ethylene promotes or flower formation in specific types of plants such as mangoes, lychees, and pineapple.
Thus, the correct answer is option D.