Find the Prime Factorization of the Number $21 \cdot 3$ B) $3 \cdot 7 \cdot 3$

Find the prime factorization of the number.
-63

A) $21 \cdot 3$
B) $3 \cdot 7 \cdot 3$
C) $7 \cdot 7 \cdot 3$
D) $3 \cdot 3 \cdot 3$