How does auxin distribution lead to phototropism?

How does auxin distribution lead to phototropism?

• A. Light stimulates cells on the illuminated side to transport or redistribute auxin to the shaded side, causing cells there to elongate and bend toward the light.
• B. Light redistributes auxin evenly.
• C. Auxin distribution is not involved in phototropism.
• D. Auxin concentrations decrease on shaded side causing bending away from light.

Answer: (A)