Find the Missing Monomial, Factor or Term $-3 x^{2} \cdot ?=-15 x^{7}$

Find the missing monomial, factor or term.
- $-3 x^{2} \cdot ?=-15 x^{7}$

A) $-5 x^{5}$
B) $x^{5}$
C) $8 x^{5}$
D) $5 x^{5}$