These are the first four women in Marine Corps history to complete infantry training. This image, which appeared Nov. 9 on the social networking site Instagram, was first published earlier Tuesday by Business Insider. It was taken by Pfc. Harlee “Rambo” Bradford, who is pictured in the center. The other three women in the photo remain unidentified. Marine officials have kept confidential the identifies of all female students attending infantry training because they are considered test subjects participating in the service’s ongoing study to determine what additional ground combat jobs should open to women. Marine Corps Times caught up with…