Suppose $$\triangle PQR$$ and $$\triangle STU$$ are congruent triangles under $$ASA$$. If $$\angle PQR = 60^\circ, \angle PRQ = 30^\circ$$ and $$\angle STU = 60^\circ$$, find $$\angle TSU$$.

A

$$90^\circ$$

B

$$75^\circ$$

C

$$60^\circ$$

D

$$45^\circ$$