In Nature,poinsettias Bloom in Early March

In nature,poinsettias bloom in early March.Research has shown that the flowering process is triggered 3 months before blooming occurs.In order to make poinsettias bloom in December,florists change the length of the light/dark cycle in September.Given this information and clues,which of the following is a correct statement about poinsettias?

A) They are short-day plants.
B) They require a light period longer than some set minimum.
C) They require a shorter dark period than is available in September.
D) The dark period can be interrupted without affecting flowering.