Question: What kinds of operations did John W. "Jack" Eskridge perform when he joined the United States Marine Corps?
Sentence (from "Jack Eskridge"): John W. "Jack" Eskridge (January 21, 1924 – February 11, 2013) was a professional basketball player who spent one season in the Basketball Association of America (BAA) as a member of the Chicago Stags and the Indianapolis Jets (1948–49).
Relevant evidence: No