Asking: 뭐예요, 누구예요, 어느 나라

A question is a statement with a rising voice

In the polite style nothing moves to make a question. 학생이에요 is I am a student; 학생이에요? with the voice rising at the end is are you a student?. Put a question word where the answer will go and the sentence is finished: 뭐예요? what is it?, 누구예요? who is it?. 뭐 is the spoken form of 무엇, and it takes 예요 because it ends in a vowel. The topic is often dropped: 이름이 뭐예요? already means what is your name?, and 직업이 뭐예요? what is your job?.

Which one: 어느 and 무슨

Two more question words go in front of a noun. 어느 picks one out of a set everyone can see or list: 어느 나라 which country, 어느 학교 which school. 무슨 asks about kind or content with no set in view: 무슨 일 what kind of work, 무슨 음식 what food. Both are followed directly by the noun, with no particle between. The most common first question to a foreigner is 어느 나라 사람이에요? – which country are you from? – and the answer reuses the pattern: 러시아 사람이에요.

어느 나라 사람이에요?Which country are you from?

이 사람은 누구예요?Who is this person?