Answer: Option A Agriculture
Step-by-step explanation: As we move towards the South and southwest some 40% of the lakes and streams are polluted this is because of the agricultural run off. The fertilizers and other pesticides leach from the soil into the water bodies which can pollute water to a great extent.
The fertilizers contains many elements which is good for plants when they leach into the water bodies they are harmful for aquatic life.
Example: Presence of mercury in fertilizers can harm the aquatic life and acts as toxins above the permissible limit.
This is the main reason the water their is very polluted and is not fishable and swimmable.