Sum of first $n$ terms of an $AP$ is $kn^2$, sum of their squares will be

Question

$(a)\;\frac{1}{6}nk^2(4n^2+1)\qquad(b)\;\frac{1}{3}nk^2(4n^2-1)\qquad(c)\;\frac{1}{3}nk^2(4n^2+1)\qquad(d)\;\frac{1}{6}nk^2(4n^2-1)$