Simplify Assume That All Variables Represent Positive Real Numbers $\sqrt { y ^ { 9 } }$

Multiple Choice

Simplify. Assume that all variables represent positive real numbers.
- $\sqrt { y ^ { 9 } }$

A) $y ^ { 8 } \sqrt { y }$
B) $y ^ { 4 } \sqrt { y }$
C) $\sqrt { \mathrm { y } ^ { 9 } }$
D) $y \sqrt { y ^ { 7 } }$