When a Nucleus at Rest Spontaneously Splits into Fragments of Mass

When a nucleus at rest spontaneously splits into fragments of mass m₁ and m₂,the ratio of the momentum of m₁ to the momentum of m₂ is

A) $- \frac { m _ { 1 } } { m _ { 1 } + m _ { 2 } }$ .
B) $- \frac { m _ { 2 } } { m _ { 1 } + m _ { 2 } }$ .
C) -1.
D) $+ \frac { m _ { 1 } + m _ { 2 } } { m _ { 1 } }$ .
E) $+ \frac { m _ { 1 } + m _ { 2 } } { m _ { 2 } }$ .