How Could Heavily Fertilized Lawns Contribute to Cyanobacterial Blooms in Lakes

How could heavily fertilized lawns contribute to cyanobacterial blooms in lakes and oceans?

A) Run-off from the lawns will get into the water system, leading to large amounts of nitrogen that can be used by cyanobacteria in water systems.
B) Nutrient-rich grass will be mowed down, with grass clipping bits eventually washing into sewer systems and into larger bodies of water. These grass clippings will serve as a nutrient source for cyanobacteria, leading to blooms.
C) Large amounts of fertilizer will lead to excessive production of greenhouse gases (like CO2) from grass in lawns. Excessive CO2 production will lead to large blooms of cyanobacteria in water systems.
D) Fertilizers contains compounds that encourage the production of bacteriochlorophylls; after rain, fertilizers get into water and are used by cyanobacteria.
E) They won't-the two systems are completely unrelated. How could grass in lawns contribute to effects in lakes and oceans?