Pheromones are . . . . . . . . in origin.

Answer: Option D

Pheromones are Exohormone and Ectohormone in origin.
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals.
Pheromones are also sometimes classified as ecto-hormones. These chemical messengers are transported outside of the body and affect neurocircuits.