Factor Completely $36 \mathrm { k } ^ { 2 } - 49 \mathrm {~m} ^ { 2 }$

Multiple Choice

Factor completely. If unfactorable, indicate that the polynomial is prime.
- $36 \mathrm { k } ^ { 2 } - 49 \mathrm {~m} ^ { 2 }$

A) $( 6 \mathrm { k } + 7 \mathrm {~m} ) ^ { 2 }$
B) prime
C) $( 6 \mathrm { k } + 7 \mathrm {~m} ) ( 6 \mathrm { k } - 7 \mathrm {~m} )$
D) $( 6 k - 7 m ) ^ { 2 }$