In first transition series, the melting point of Mn is low because

Question

$\begin{array}{1 1}(a)\;\text{Due to }d^1\text{ configuration, metallic bonds are strong}\\(b)\;\text{Due to }d^5\text{ configuration, metallic bonds are weak}\\(c)\;\text{Due to }d^7\text{ configuration, metallic bonds are weak }\\(d)\;\text{None of these}\end{array}$