Answer:
A.
Nutrients from fertilizers on the farm wash off into the lake and cause the green slimy algal bloom
Step-by-step explanation:
This question describes a team of marine biologists, who observe an inland sea covered up with a green slime. Firstly, this green slime is the the visible form of the proliferated growth of algae, hence, causing what is referred to as ALGAL BLOOM.
Algal bloom is caused by EUTROPHICATION, which is the pollution of water bodies with nutrients from fertilizers e.g phosphate, nitrate etc which causes a rapid algae growth. The excessive nutrients causing this algal bloom appearing like a green slime comes from the fertilizers used by farmers practising large scale farming within that area.
When this fertilizer is applied on plants, it gets washed into the water body and its constituents e.g phosphorus, nitrogen etc. serves as source of nutrient for the growth of marine organisms (algae). Hence, they grow excessively and form a bloom that appears like a green slime on the lake.
Hence, the farming activities is releasing pollutants in form of chemical substances which serve as nutrients for the proliferated growth of algae.