Which of the following are considered autotrophic components within a…

The correct answer is Option (4) → All of the above

Autotrophs are the organisms that make their own food by photosynthesis. In a pond, NCERT names the phytoplankton, some algae, and the floating, submerged and marginal plants at the edges as the autotrophic components. All three listed groups are therefore autotrophs.

Option (1) Phytoplankton — Correct statement, but it is only one of the correct points, so on its own it is not the answer. Phytoplankton are tiny photosynthetic organisms floating in the water.

Option (2) Algae — Correct statement, but it is only one of the correct points, so on its own it is not the answer. Some algae of the pond also carry out photosynthesis.

Option (3) Submerged and marginal plants — Correct statement, but it is only one of the correct points, so on its own it is not the answer. Submerged and marginal plants growing at the edges of the pond are autotrophs too.

NCERT Extract:
Ecosystem – Structure and Function – “… The abiotic component is the water with all the dissolved inorganic and organic substances and the rich soil deposit at the bottom of the pond. The solar input, the cycle of temperature, day-length and other climatic conditions regulate the rate of function of the entire pond. The autotrophic components include the phytoplankton, some algae and the floating, submerged and marginal plants found at the edges. The consumers are represented by the zooplankton, the free swimming and bottom dwelling forms.”