Please answer this aassertion-reason question as per aiims pattern:

Assertion: High concentration of auxin inhibit root and shoot growth.

Reason: Ethylene is produced in high Auxin concentration.

Ans is A, both statements are correct.
AUXIN promotes root initiation, but at high concentration auxin inhibits root elongation.
AUXIN also promotes shoot apical dominance, at high concentration it promotes synthesis of ethylene in lateral buds and causes inhibition of shoot growth.