The correct option is A They have a direct role in photosynthesis, respiration and reproduction
Metabolites are substances involved in metabolic pathways. Photosynthesis, respiration and reproduction are metabolic pathways and metabolites having a direct role in them are called primary metabolites.
Metabolites which do not have a direct role in the growth and development of an organism are called secondary metabolites. They include chemical compounds of diverse nature, such as pigments, toxins, drugs, lectins, gums and resins. They are not involved directly in the metabolic pathways such as photosynthesis, respiration and reproduction. Their distribution is restricted to a limited taxonomic group.