(A) Grunt
(B) Jarhead
(C) Gang Gang
(D) ** GI
EXPLANATIONS BELOW
Concept note-1: -Originally, GI stood for “Galvanized Iron”, the primary material used to make military items, i.e. buckets. However, as the military grew and evolved over time, GI took on multiple meanings, including “Government Issue”, “General Issue”, and even “Ground Infantry”.
Concept note-2: -The term G.I. has been used as an initialism of “Government Issue", “General Issue", or “Ground Infantry", and was used by the logistics services of the United States Armed Forces.
Concept note-3: -GI Joe in American English US. Slang. any man in the U.S. armed forces; esp., an enlisted soldier in WWII. Webster’s New World College Dictionary, 4th Edition.
Concept note-4: -Soldiers used condoms to protect their “other weapons” by covering the muzzles of their gun to prevent mud and other material from clogging the barrel. This practice lasted up into the Vietnam War, during which American soldiers slid condoms onto their M-16s. Condoms made sure the rifle was ready instantly.