Find the Exact Value Of $\log _ { 8 } \sqrt [ 3 ] { 64 }$

Find the exact value of $\log _ { 8 } \sqrt [ 3 ] { 64 }$ without using a calculator.

A) $\frac { 64 } { 3 }$
B) $\frac { 3 } { 64 }$
C) $\frac { 16 } { 3 }$
D) $\frac { 2 } { 3 }$
E) $- 1$