Final answer:
The Selected Marine Corps Reserve Medal was established in 1939 to honor Marine Corps reservists for four years of honorable service.
Step-by-step explanation:
The Selected Marine Corps Reserve Medal (SMCRM) was established in the year 1939. It is awarded to members of the Marine Corps Reserve who, after July 1, 1925, have performed four years of honorable active reserve service. This medal is a way to recognize the dedication and commitment of reservists who play a crucial role in the readiness and operational capability of the Marine Corps.