Question

Triangle ABC is similar to triangle PQR, as shown below:

Two similar triangles ABC and PQR are shown. Triangle ABC has sides AB = c, BC = a, and AC = b. Triangle PQR has sides PQ = r, QR = p, and PR = q. Angle CAB is congruent to angle RPQ. Angle ABC is congruent to angle RQP. Angle ACB is congruent to angle QRP.

Which ratio is equal to p:a?
a:r
p:b
r:c
q:c