Which Numbers in the Following Set Are Irrational Numbers $$\left\{ \frac { 1 } { 9 } , 7 , \sqrt { 7 } , \pi , - 0.4 \right\}$$

Multiple Choice

Which numbers in the following set are irrational numbers? $$\left\{ \frac { 1 } { 9 } , 7 , \sqrt { 7 } , \pi , - 0.4 \right\}$$

A) $\sqrt { 7 } , \pi$
B) $\sqrt { 7 } , \pi , - 0.4$
C) $\frac { 1 } { 9 } , 7 , \sqrt { 7 } , \pi , - 0.4$
D) $\frac { 1 } { 9 } , 7 , - 0.4$