Which of the following is a biofertilizer?

Answer: Option A

Fertilizer is the supplement added to the soil and plants to fulfill the nutrient deficiency in any plant and increase the fertility of the soil, it is usually a chemical supplement Whereas, Biofertilizers are living microbes that enhance plant nutrition by either mobilizing or increasing nutrient availability in soils.
Here, Green algae are the Biofertilizer used to increase yield and soil fertility and are mostly used in Rice fields.