Read the sentences below. The new safety requirements were enacted based on scientists’ recommendations. Fewer accidents occurred.

Which combines the sentences to create one complex sentence?

The new safety requirements were enacted based on scientists’ recommendations; fewer accidents occurred.
Based on the scientists’ recommendations, the new safety requirements were enacted, and fewer accidents occurred.
Based on the scientists’ recommendations, the new safety requirements were enacted so that fewer accidents occurred.
The new safety requirements were enacted based on scientists’ recommendations, and fewer accidents occurred.