During time of Tet, the streets are crowded because people go shopping

A. During time of Tet, the streets are crowded but people go shopping.

B. During time of Tet, people go shopping, so the streets are crowded.

C. During time of Tet, the streets are not crowded because people go shopping.

D. During time of Tet, people go shopping and the streets are not crowded.