What is the permitted disparity for a defined contribution plan with a current base contribution percentage of $6\%?$

A$)$

$5\mathrm{.}7\%$

B$)$

$11\mathrm{.}7\%$

C$)$

$12\mathrm{.}0\%$

D$)$

$6\mathrm{.}0\%$