Which step should be used to prove that point P is equidistant from points R and Q?
A. In triangles PRS and PQS, all three angles are equal.
B. If two sides and one included angle are equal in triangles PQS and PRS, then their third sides are equal.
C. In triangles PQR and PQS, if one side and one angle are equal, then their corresponding sides and angles are also equal.
D. If any one side and anyone common angle are equal in triangles PQR and PRS, then their corresponding sides are also equal.