I thought another name for Multiplexor was Mux, but after doing some google search I got an answer which said "Data Selector" no where else can I see that, I mean not in my notes or any other websites
Mux is simply short for multiplexer, so I don't know if that satisfies as "another name" or not for your purposes. It might be what they are looking for, especially if you are sure that no other name has been mentioned in your course/text.
Don't "data selector" or "input selector" seem like reasonable names?