Concept:
Crystal faces develop during crystal growth. Their relative sizes are controlled by the growth conditions and degree of crystallization.
Step 1: Understand crystal faces.
A crystal face is a plane surface developed during crystal growth.
Step 2: Effect of crystallization.
If crystallization conditions are favourable, crystal faces develop properly. If conditions are not uniform, some faces may grow larger and others may remain smaller.
Step 3: Final conclusion.
Thus, the relative size and shape of a crystal face depends mainly on the degree of crystallization.
\[
\therefore \text{Correct Answer is (B)}
\]