Final answer:
National Guard/Reserve members are eligible for TRICARE Reserve Select when on active service for 30 days or less.
Step-by-step explanation:
When on active service for 30 days or less, National Guard/Reserve members are eligible for TRICARE Reserve Select. TRICARE Reserve Select is a premium-based health insurance plan that offers comprehensive health coverage. This benefit is available to National Guard/Reserve members and their families when they are on active duty orders for 30 days or less.