Answer
$1.38Mev$
Work Step by Step
First of all, we find the mass difference as
$\Delta m=m_f-m_i$
$\implies \Delta m=210.98726u-210.9887u=-0.00148u$
Now we can find the energy released as:
$E=|\Delta m|c^2$
We plug in the known values to obtain:
$E=0.00147(931.5Mev/c^2)c^2=1.38Mev$
