A wire can be broken by applying a load of $20 \mathrm{~kg}$ wt. The force required to break the wire of twice the diameter is
(a) $20 \mathrm{~kg} \mathrm{wt}$
(b) $5 \mathrm{~kg} \mathrm{wt}$
(c) $80 \mathrm{~kg} \mathrm{wt}$
(d) $160 \mathrm{~kg}$ wt