n enum has default modifier as public

A class has default modifiers as private . It can declare members (methods etc) with following access modifiers:
public
internal
private
protected internal

An interface has default modifier as public

A struct has default modifier as private and it can declare its members (methods etc) with following access modifiers:
public
internal
private

A methods, fields, and properties has default access modifier as “Private” if no modifier is specified.