The soil is poisoned because farmers use too many pesticides and herbicides

A. Famers use too many pesticides and herbicides, but the soil is poisoned.

B. Famers use too many pesticides and herbicides, for the soil is poisoned.

C. Famers use too many pesticides and herbicides, so the soil is poisoned.

D. Famers use too many pesticides and herbicides, or the soil is poisoned.