Solve the Differential Equation $$y ^ { tt } - 4 y ^ { t } + 20 y = 0$$

Multiple Choice

Solve the differential equation.
$$y ^ { tt } - 4 y ^ { t } + 20 y = 0$$

A) $y ( x ) = e ^ { 2 x } \left( c _ { 1 } \cos ( 4 x ) + c _ { 2 } \sin ( 4 x ) \right)$
B) $y ( x ) = e ^ { 2 x } \left( c _ { 1 } \cos ( 2 x ) + c _ { 2 } x \sin ( 2 x ) \right)$
C) $y ( x ) = e ^ { 4 x } \left( c _ { 1 } \cos ( 2 x ) + c _ { 2 } \sin ( 2 x ) \right)$
D) $y ( x ) = c e ^ { 2 x } \cos ( 4 x )$
E) $y ( x ) = e ^ { 2 x } \left( c _ { 1 } \cos ( 4 x ) + c _ { 2 } x \sin ( 4 x ) \right)$