When a Stationary Plutonium-239 ${ } _ { 94 } ^ { 239 } \mathrm { Pu }$

Multiple Choice

When a stationary plutonium-239, ${ } _ { 94 } ^ { 239 } \mathrm { Pu }$ , decays into uranium-235 plus an alpha particle, the energy released in the process is $5.24 \mathrm { MeV }$ . The following masses are known:
${ } _ { 2 } ^ { 4 } \mathrm { He } : \quad 4.002603 \mathrm { u }$
${ } _ { 92 } ^ { 235 } \mathrm { U } : \quad 235.043924 \mathrm { u }$
What is the mass of the ${ } _ { 94 } ^ { 239 } \mathrm { Pu }$ nucleus, in amu? $\left( 1 \mathrm { u } = 931.494 \mathrm { MeV } / \mathrm { c } ^ { 2 } \right)$

A) $239.00189 \mathrm { u }$
B) $239.02775 \mathrm { u }$
C) $238.98884 \mathrm { u }$
D) $239.05215 \mathrm { u }$
E) $238.99919 \mathrm { u }$