Solve the Equation and Express the Solution in Exact Form $\log _ { 4 } ( x + 1 ) + \log _ { 4 } ( x - 1 ) = 2$

Multiple Choice

Solve the equation and express the solution in exact form.
- $\log _ { 4 } ( x + 1 ) + \log _ { 4 } ( x - 1 ) = 2$

A) $\left\{ \frac { 3 } { 2 } \right\}$
B) $\{ 17 \}$
C) $\{ \sqrt { 17 } \}$
D) $\{ 8 \}$