Fill in the Blank with One of the Words or Phrases

Multiple Choice

Fill in the blank with one of the words or phrases listed below. $$\begin{array} { l l l } \text { index rationalizing } & \text { conjugate } & \text { principal square rootcube root midpoint } \\\text { complex numberlike radicals } & \text { radicand } & \text { imaginary unit } \quad \text { distance }\end{array}$$
-In the natation n is called the and a is called the ---------------

A) index, conjugate
B) conjugate, radicand
C) index, radicand
D) radicand, index