Find the Zeros of the Function Below Algebraically, If Any $$f ( x ) = x ^ { 4 } + 8 x ^ { 2 } + 15$$

Multiple Choice

Find the zeros of the function below algebraically, if any exist.
$$f ( x ) = x ^ { 4 } + 8 x ^ { 2 } + 15$$

A) $- \sqrt { 5 } , - \sqrt { 3 } , \sqrt { 3 }$ , and $\sqrt { 5 }$
B) $- \sqrt { 3 } , 0$ , and $\sqrt { 3 }$
C) $- \sqrt { 3 }$ and $\sqrt { 3 }$
D) $- \sqrt { 5 }$ and $\sqrt { 5 }$
E) No zeros exist.