Answer:
The correct answer would be A. nitrate and glucose.
Auxin or Indole-3-acetic acid is a plant hormone which regulates the growth of the plants.
The biosynthesis of the auxin uses tryptophan as the precursor. Tryptophan is first converted to IPA (another amino acid) which is then converted to IAA (Indole-3-acetic acid).
Similarly, the biosynthesis of tryptophan is started from shikimic acid (cyclohexane) or anthranilate (aromatic acid).
Thus, ultimately it requires glucose and nitrogen form the production of auxin.
In addition, the given picture shows that auxin is composed of carbon, hydrogen, nitrogen, and oxygen. All the molecules required for the production of auxin can be provided by glucose and nitrate.
