For which value of kkk is 2016+56\sqrt{2016} + \sqrt{56}2016+56 equal to 14k14^k14k?(A) 12\frac{1}{2}21 (B) 34\frac{3}{4}43 (C) 54\frac{5}{4}45 (D) 32\frac{3}{2}23 (E) 52\frac{5}{2}25