Which sentence correctly forms the plural of 1900?
AWas the helicopter invented in the 1900s?
BWas the helicopter invented in the 1900's?<=my ans b
CWas the helicopter invented in the 1900s'?
AWas the helicopter invented in the 1900s?
BWas the helicopter invented in the 1900's?<=my ans b
CWas the helicopter invented in the 1900s'?