If the standard deviation of the numbers 2, 3, a and 11 is 3.5, then which of the following is true ?

Question

( A ) $3a^2−23a+44=0$
( B ) $3a^2−26a+55=0$
( C ) $3a^2−32a+84=0$
( D ) $3a^2−26a+55=0$