What does S. P.Q. R. mean?

Senatus Populusque Romanus

Explanation:

In the time of the Roman Republic the Standards were imprinted with the letters SPQR which was an abbreviation for Senatus Populusque Romanus (Senate and People of Rome). The Standard, then, represented not only the legion or cohort which carried it but the citizens of Rome, and the policies the army represented.

when in doubt choose c

it's what my teacher told my class when we were going into psats