NADP (nicotinamide adenine dinucleotide phosphate) is a coenzyme that plays an important role in many metabolic processes, including photosynthesis, cellular respiration, and biosynthesis of macromolecules. NADP+ can be reduced to NADPH by accepting two electrons and a hydrogen ion (H+).

HMP pathway:

The HMP (hexose monophosphate) pathway, also known as the pentose phosphate pathway, is a metabolic pathway that occurs in the cytoplasm of cells. It is an alternative pathway to glycolysis for glucose metabolism. The HMP pathway has two main functions: to produce NADPH and to generate pentoses (5-carbon sugars) for nucleic acid synthesis. NADPH is an important reducing agent in many biosynthetic reactions, including fatty acid synthesis, cholesterol synthesis, and detoxification of reactive oxygen species.

Calvin cycle:

The Calvin cycle is a series of biochemical reactions that occur in the stroma of chloroplasts during photosynthesis. The Calvin cycle is responsible for converting carbon dioxide (CO2) into organic compounds, such as glucose, using the energy from ATP and NADPH produced during the light-dependent reactions. NADPH is an essential source of reducing power for the Calvin cycle, which helps to drive the synthesis of organic molecules from inorganic carbon.

Glycolysis:

Glycolysis is a metabolic pathway that occurs in the cytoplasm of cells. It is the first step in the breakdown of glucose to produce energy in the form of ATP. During glycolysis, glucose is converted into two molecules of pyruvate, generating energy and producing two molecules of NADH. However, NADH is not the same as NADPH and cannot be used directly as a reducing agent in biosynthetic reactions.

EMP pathway:

The EMP (Embden-Meyerhof-Parnas) pathway, also known as glycolysis, is a metabolic pathway that occurs in the cytoplasm of cells. It is the main pathway for glucose metabolism and is used to produce energy in the form of ATP. However, like glycolysis, the EMP pathway does not produce NADPH and cannot be used directly as a source of reducing power for biosynthetic reactions.

Conclusion:

Therefore, the correct answer is option 'A', HMP pathway. The HMP pathway is the only pathway mentioned that specifically produces NADPH, which is an important source of reducing power for biosynthetic reactions. Moreover, the HMP pathway is an alternative pathway to glycolysis for glucose metabolism, which allows for the production of pentoses for nucleic acid synthesis.

The pentose phosphate pathway also called the phosphogluconate pathwayand the hexose monophosphate shunt is a metabolic pathway parallel to glycolysis. It generates NADPH and pentoses 5-carbon sugars as well as ribose 5-phosphate, the last one a precursor for the synthesis of nucleotides.