the question asks us for PRS - PQS... so in triangle PQS, 180 = RSP + SPR + RPQ + PQR, so angle RPQ is the difference between the two angles in question. We can restate the question as "what is angle RPQ"

so A is suff

B is suff by knowing 180 - given angles

so D

Okay l got D as an answer too
I have reattached your diagram with the angles numbered from 1 to 5 to avoid confusion what we are required to find is :angle 4 - angle 2
angle 4 + angle 5 = 90.....(l)
Angle 1 + Angle 2 + Angle 5 = 90

from statement( 1)
angle 1 =30
thus angle 2+ angle 5 = 60.....(ll)

subtract (ll) from (l) you get angle 4 - angle 2

Statement (2) basically says the same thing ... that angle 1 =30

I hope that helped



angle