Find the Greatest Common Factor of the Expressions Below, If $40 ( 7 - y ) ^ { 5 } , 50 ( 7 - y ) ^ { 4 }$

Multiple Choice

Find the greatest common factor of the expressions below, if one exists. $40 ( 7 - y ) ^ { 5 } , 50 ( 7 - y ) ^ { 4 }$

A) $40 ( 7 - y ) ^ { 4 }$
B) $5 ( 7 - y ) ^ { 10 }$
C) $10 ( 7 - y ) ^ { 4 }$
D) $4 ( 7 - y ) ^ { 5 }$
E) No greatest common monomial factor exists.