For What Value Of $a$ Does the Equation $x ^ { 2 } + y ^ { 2 } - a x + 4 y + - 3 = 0$

Multiple Choice

For what value of $a$ does the equation $x ^ { 2 } + y ^ { 2 } - a x + 4 y + - 3 = 0$ represent a circle with center $( 3 , - 2 )$ ? When $a$ assumes this value, what is the radius of the circle?

A) $\quad a = 4 , \quad$ radius $= 5$
B) $\quad a = 7 , \quad$ radius $= 6$
C) $\quad a = 6 , \quad$ radius $= 4$
D) $\quad a = 5 , \quad$ radius $= 5$
E) $\quad a = 5 , \quad$ radius $= 3$