What happens to a function defined inside a class without any complex operations (like looping, a large number of lines, etc)?

Question: What happens to a function defined inside a class without any complex operations (like looping, a large number of lines, etc)?

1.It becomes a virtual function of the class

2.It becomes a default calling function of the class

3.It becomes an inline function of the class

4.The program gives an error

Answer:3