List All the Elements of B That Belong to the Given

Multiple Choice

List all the elements of B that belong to the given set.
- $$B = \left\{ 4 , \sqrt { 7 } , - 23,0 , \frac { 4 } { 9 } , - \frac { 9 } { 4 } , 2.2 \right\}$$
Natural numbers

A) $\{ 4 \}$
B) $\{ - 23,0,4 \}$
C) $\left\{ 4,0 , - \frac { 9 } { 4 } \right\}$
D) $\{ 4,0 \}$