Find All Valid Real Roots for the Equation $$x ^ { 8 } = 5 x ^ { 4 } - 4$$

Multiple Choice

Find all valid real roots for the equation.
- $$x ^ { 8 } = 5 x ^ { 4 } - 4$$

A) $x = \pm \sqrt [ 4 ] { 1 } , x = \pm \sqrt [ 4 ] { 4 }$
B) $x = 1 , x = 4$
C) $x = \pm 1 , x = \pm \sqrt [ 4 ] { 4 }$
D) $x = \pm \sqrt [ 4 ] { 1 } , x = 4$