Which Two Radicals Are Like?
A) $- 7 \sqrt { 3 }$

Multiple Choice

Which two radicals are like?

A) $- 7 \sqrt { 3 }$ and $\frac { \sqrt { 3 } } { 5 }$
B) $3 \sqrt { 21 }$ and $- \sqrt [ 3 ] { 21 }$
C) $\sqrt { 3 }$ and $\sqrt { 7 }$
D) $3 \sqrt { 21 }$ and $3 \sqrt { 7 }$