Concept:Seed dormancy is the natural state that keeps seeds from germinating, and it is controlled by plant hormones.
Explanation:Abscisin, also known as abscisic acid, is the hormone that inhibits growth and maintains seed dormancy.
It stops the embryo from growing, so the seeds will not sprout during the three-year storage period.
Gibberellins do the opposite because they actively promote germination and sprouting, which must be avoided.
Cytokinins encourage cell division and plant growth, so they would not keep seeds dormant.
Auxin stimulates cell elongation and general growth, but it is not responsible for enforcing dormancy.
Therefore, treating the seeds with abscisin is the correct method to prevent them from sprouting for three years.
Answer:C. abscisin