1) Asker 2) Emcee 1) Asker 2) Enquirer 3) Inquirer 4) Querier 5) Questioner 
• (n.) One who interviews; especially, one who obtains an interview with another for the purpose of eliciting his opinions or obtaining information for publication.
In'ter·view`er noun One who interviews; especially, one who obtains an interview with another for the purpose of eliciting his opinions or obtaining information for publication. « It would have made him the prince of interviewers in these days.» Leslie Stephen. 
[n] - a person who conducts an interview
Person involved in the collection of data for market, opinion and social research purposes.
a person who interviews. · a peephole in an entrance door.