b
(b) $v \propto {g^p}{h^q}$ (given)
By substituting the dimension of each quantity and comparing the powers in both sides we get $[L{T^{ - 1}}] = {[L{T^{ - 2}}]^p}{[L]^q}$
$ \Rightarrow $ $p + q = 1,\,\, - 2p = - 1,\,$
$\therefore \,\,p = \frac{1}{2},\,q = \frac{1}{2}$