Answer:
(C)Angle MRN and Angle NRO
Explanation:
A diagram of the given problem is drawn and attached below.
From the diagram:
Option A: Angle PRL and Angle LRM = Angle PRM which is not 180 degrees.
Option B: Angle ORP and Angle MRN are vertically opposite angles and are therefore not linear pairs.
Option C: Angle MRN and Angle NRO are on the line ORM and therefore forms a linear pair.
Therefore, the correct option is C.