In Mendel's experiments with garden pea,round seed shape $(RR)$ was dominant over wrinkled seeds $(rr)$,and yellow cotyledon $(YY)$ was dominant over green cotyledon $(yy)$. What are the expected phenotypes of the $F_1$ generation when a homozygous round yellow plant $(RRYY)$ is crosseded with a homozygous wrinkled green plant $(rryy)$?

• A
  Round seeds with yellow cotyledons
• B
  Only round seeds with green cotyledons
• C
  Only wrinkled seeds with yellow cotyledons
• D
  Only wrinkled seeds with green cotyledons