Question

select all the pairs of alternate exterior angles.

Explanation:

Step1: Recall alternate - exterior angles definition

Alternate - exterior angles are non - adjacent angles that lie outside two lines and on opposite sides of a transversal.

Step2: Analyze the given angles

In the figure, lines MO and PR are intersected by transversal LS.
For the pair $\angle ONL$ and $\angle PQN$, they are non - adjacent, lie outside lines MO and PR and on opposite sides of transversal LS.
For the pair $\angle MNL$ and $\angle RQS$, they are non - adjacent, lie outside lines MO and PR and on opposite sides of transversal LS.
For the pair $\angle ONL$ and $\angle PQS$, they are non - adjacent, lie outside lines MO and PR and on opposite sides of transversal LS.

Answer:

$\angle ONL$ and $\angle PQN$, $\angle MNL$ and $\angle RQS$, $\angle ONL$ and $\angle PQS$