ATP formation occurs through which of the following?

Correct option is D. All of these
In the process of photosynthesis, the phosphorylation of ADP to form ATP using the energy of sunlight is called photophosphorylation.
Oxidative phosphorylation is the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers. This process, which takes place in mitochondria, is the major source of ATP in aerobic organisms.
Substrate-level phosphorylation is a metabolic reaction that results in the formation of ATP or GTP by the direct transfer of a phosphoryl group to ADP or GDP from another phosphorylated compound.
Hence, ATP formation occurs through Photophosphorylation, Oxidative phosphorylation and Substrate level phosphorylation.
So, the correct answer is 'All of these'