Auxin is discovered by?

• The word auxin means "to grow".Auxin is one of the major plant hormones. It was discovered by Charles Darwin and his sons Francis. 
• It plays an important role in embryonic development, elongation, differentiation, cell division, apical dominance, and flowering.
• It is also helpful in the healing process of the plant.
• Apical meristem of seed shoots and young shoots is the site for the production of the auxin hormone.
• With the gibberellin, auxin help in the development of the fruit.
• Auxin hormone travels in the downward direction from the site of production.

Hence, option C is the correct answer.