Explanation
The question wants us to select the answer choice that shows the set of irrational numbers that is not closed under the addition.
Form the options given
[tex]\begin{gathered} \pi+(-\pi)=0 \\ is\text{ not closed} \end{gathered}[/tex]
Because,
[tex]\begin{gathered} \pi\text{ is an irrational number} \\ But\text{ 0 is a rational number} \end{gathered}[/tex]
Thus the answer is the first option
[tex]\pi+(-\pi)=0[/tex]
