Parts of a sentence are given below. While the first part (S1) is in the correct place, the remaining parts (labelled P, Q, R and S) are jumbled up. Arrange the parts in the correct order to form a meaningful and coherent sentence. The sun began to set, (S1) / casting a golden glow over the fields (P) / as the sky turned orange and pink (Q) / while the birds chirped their evening songs (R) / creating a picturesque scene (S).

1. PQRS
2. SPRQ
3. RSPQ
4. QRSP