$2\mathrm{.}3$ A surface footing $1m4m$ on a clayey soil with $=0$ has the ultimate bearing capacity of $4$q$.$ Which one of the following is the correct value of ultimate bearing capacity for a surface footing $2\mathrm{.}5m4m$ on the same soil?

$($a$)q$

$($b$)4q$

$($c$)10q$

$($d$)16q$

$[$CSE : $2001]$