What is the reciprocal of $\;3+ \sqrt{7} i$ ?

Question

$(a)\;\large\frac{11}{16} - \large\frac{\sqrt{7}}{16} i\qquad(b)\;\large\frac{3}{16} - \large\frac{\sqrt{7}}{16} i\qquad(c)\;\large\frac{7}{16} - \large\frac{\sqrt{5}}{16} i\qquad(d)\;\large\frac{3}{16} - \large\frac{\sqrt{5}}{16} i$