Post-operative nausea and vomiting (PONV) is more common in older patients, not younger ones. While **age < 3 years** is associated with **lower** risk of PONV, it is not a risk factor — in fact, it's protective. Risk factors include **longer anesthesia duration**, **personal or family history of PONV**, and **motion sickness history**, which are linked to increased sensitivity. Younger children have less incidence of PONV due to immature central nervous system responses.

**✓ Correct: A. Age < 3years**