[A]: Heterosis is superiority of `F_1` hybrid over its two genetically dissimilar parents.
[R]: Heterosis can be measured in terms of size, yield and growth rate
A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false