Select the phrase/connector from the given three options which can be used to form a single sentence from the two sentences given below, implying the same as expressed in the statement sentence.
The most effective known method for erosion prevention is to increase vegetative cover on the land. It helps prevent both wind and water erosion.
1. For it helps
2. Which helps
3. As the most
1
Only 1
2
Only 2
3
Only 3
4
Both 1 and 3
5
Both 2 and 3