Question

In a Food chain, the largest population is that of
A. Producers
B. Decomposers
C. secondary consumers
D. Primary consumers.

Answer 1

Autotrophs are the organism which are larger in the number in the food chain. Which support the large numbers of herbivores. It shows an upright pyramid but in some cases it shows a spindle shaped.

Complete answer:
Producers are the organisms which form food in the food chain and present at the base of the food chain pyramid. Producers form food by the use of sunlight by fixing $C{O_2}$ and ${H_2}O$ and accumulate in their body as biomass and make available energy to the other organisms of the food chain, without producers food chains do not exist in nature. It shows an upright pyramid but in some cases it shows a spindle shaped pyramid in a different ecosystem.
Primary consumers are also called herbivorous animals which feed on producers and convert the producers biomass into the animal biomass which is necessary to transfer the energy to the next trophic level and make available energy to the successive food chain members of trophic level. After the Producers, primary consumers play a significant role in converting the plant biomass to animal biomass which act as food for secondary consumers and tertiary consumers.
Tertiary consumers sometimes represent the top carnivorous or top predators which feed on the primary consumers, primary carnivorous or secondary consumers to maintain the food chain balance.
Decomposers: it represent the micro consumers which play a significant role in the ecosystem, they demineralized the organic matter and made available mineral and nutrient in the ecosystem, without these recycle of minerals is stop or may slow down which is not good for ecosystem and decomposer show detritus food chain in the ecosystem.

Hence, the correct option is A. producers.

Note:
The largest number of population is producers but it varies due to different types of ecosystem but majorly producers represents the larger number of population.