Final answer:
CHCBP must be purchased within 60 days after TRICARE eligibility ends, providing transitional health coverage for 18 to 36 months.
Step-by-step explanation:
The Continued Health Care Benefit Program (CHCBP) must be purchased within 60 days of when TRICARE eligibility ends. It is a premium-based plan that offers temporary transitional health coverage for 18 to 36 months after TRICARE eligibility ends. It acts as a bridge between military health benefits and civilian health plans.