Which one of the following is representing the group of diatoms?

A. Pinnularia, Navicula, Cymbella, Melosira
B. Euglenamorpha, Hedneria , Heteronema, Colacium
C. Nostoc, Anabaena, Aulosira, Cylindrospermum
D. Cochlodinium, Gymnodinium, Lenodinium, Peridinium