- A Prophase, prior to S phase
- B S phase (DNA replication)
- C Metaphase, before anaphase
- D G1 phase, before S phase
Correct answer: B. S phase (DNA replication)
Explanation: Cohesin rings are loaded onto chromosomes and establish sister chromatid cohesion during DNA replication in S phase.
Concept context
Mitosis and meiosis: how cells divide for growth, repair, and reproduction.