The algal blooms can be defined as the rapid growth of the algae in the water bodies. These algal blooms are a result of the excess amounts of nutrients, such as phosphorus, in the water. These excess nutrients are released in the fresh water bodies as a result of the fertilizers that are washed away from the agricultural fields nearby. The fertilizers are rich in nutrients such as phosphorus to help the plant to grow. When they get washed into the water bodies, they promote the growth of the algae leading to algal bloom.
Hence, the correct answer is 'Option C - The nutrients are a part of the fertilizers that are often washed away into ponds'.