Selaginella Is a Heterosporous Lycophyte

Selaginella is a heterosporous lycophyte.If you want to study Selaginella gametophyte structure, the most important reason why you must collect more than one sample is

A) to ensure genetic diversity in your sample.
B) because the structure of the microgametophyte changes so much as it develops into a megagametophyte.
C) because more samples are always better than one.
D) in case the first one dies.
E) because microgametophytes have a different structure than the megagametophytes.