d
$P = \frac{{{V^2}}}{R}$ so $R = \frac{{{V^2}}}{P}$
${R_1} = \frac{{{V^2}}}{{100}}$ and ${R_2} = {R_3} = \frac{{{V^2}}}{{60}}$
Now ${W_1} = \frac{{{{(250)}^2}}}{{{{({R_1} + {R_2})}^2}}}.{R_1}$, ${W_2} = \frac{{{{(250)}^2}}}{{{{({R_1} + {R_2})}^2}}}.{R_2}$
and ${W_3} = \frac{{{{(250)}^2}}}{{{R_3}}}$
${W_1}:{W_2}:{W_3} = 15:25:64$ or ${W_1} < {W_2} < {W_3}$