A smaller number of Marine Corps officers may be commissioned via the Marine Corps Platoon Leaders Class (PLC) program during summers while attending college. PLC is a sub-element of Marine Corps OCS and college and university students enrolled in PLC undergo military training at Marine Corps Officer Candidate School in two segments: the first of six weeks between their sophomore and junior year and the second of seven weeks between their junior and senior year. There is no routine military training during the academic year for PLC students as is the case for ROTC cadets and midshipmen, but PLC students are routinely visited and their physical fitness periodically tested by Marine Corps Officer Selection Officers (OSOs) from the nearest Marine Corps officer recruiting activity. PLC students are placed in one of three general tracks: PLC-Air for prospective Marine Naval Aviators and Marine Naval Flight Officers; PLC-Ground for prospective Marine infantry, armor, artillery and combat support officers; and PLC-Law, for prospective Marine Corps judge advocate general officers. Upon graduation from college, PLC students are commissioned as active duty 2nd lieutenants in the U. S. Marine Corps Reserve, with the option to augment their commissions to the regular Marine Corps after five to ten years of commissioned service.