Find All Valid Real Roots for the Equation $$3 x ^ { 8 } + 4 x ^ { 4 } = 32$$

Multiple Choice

Find all valid real roots for the equation.
- $$3 x ^ { 8 } + 4 x ^ { 4 } = 32$$

A) no real roots
B) $x = \sqrt [ 4 ] { 4 }$
C) $x = \pm \frac { \sqrt [ 4 ] { 216 } } { 3 } , x = \sqrt [ 4 ] { 4 }$
D) $x = \pm \frac { \sqrt [ 4 ] { 216 } } { 3 }$