Answer:
The correct answer would be group D- 809 kg.
It can be explained with the help of pyramid of biomass.
Pyramid of biomass represents biomass or the amount of organic or living matter present at each trophic level in an ecosystem.
The amount of organic matter is usually expressed in grams per meter square (g/m²).
There are usually four trophic levels in the pyramid of biomass: primary producers, primary consumers, secondary consumers, and tertiary consumers.
Usually, the biomass decreases as we go up the trophical levels specially in terrestrial ecosystem. Inverted pyramid can be observed in case of aquatic ecosystem (biomass of phytoplanktons is less than that of herbivores).
Here, maximum biomass (809 kg) belongs to the group D and hence, it would belong to primary producers.