The Owner of a Plant Nursery Is Introducing the New

The owner of a plant nursery is introducing the new night janitor to his duties."Behind this door are the poinsettias," she said,"Please don't clean this room,and leave the door closed." Why might the owner say this?

A) Poinsettias are short-day plants that require a long uninterrupted period of darkness to flower.Even a short flash of light at night could prevent flowering.
B) Poinsettias are very sensitive to the chemicals used in cleaning,which can interfere with the gibberellin-dependent pathway and disrupt flowering.
C) Poinsettias are tropical plants and require constant warm temperatures for flower formation.
D) Poinsettias are long-day plants that require a long period of light for flower formation,and this light might disrupt the day-night cycles of other plants outside the room.