In a right-angled triangle PQR, right-angled at Q, the length of the side PR is 17 units, length of the base QR is 8 units, and length of the side PQ is 15 units. If $$\angle RPQ = \alpha$$, then sinα + cosα is:

A

$$\frac{18}{17}$$

B

$$\frac{23}{17}$$

C

$$\frac{21}{17}$$

D

$$\frac{15}{17}$$