In a $\Delta$ABC if the sides are $a=3,b=5,c=4$ then $\sin\large\frac{B}{2}$$+\cos{\large\frac{B}{2}}$ is equal to

Question

$\begin{array}{1 1}(a)\;a^2&(b)\;b^2\\(c)\;c^2&(d)\;None\;of\;these\end{array}$