Say that string x is a prefix of string y if a string z exists where xz = y and that x is a proper prefix of y if in addition x!=y. Suppose an operation is defined on a regular language A. In which of the following options, the class of the regular language is closed? The answer given is a.
- NOPREFIX(A) = {w ∈ A | no proper prefix of w is a member of A}
- EXTEND(A) = {w ∈ A | w is the proper prefix of any string in A}
- PREFIX(A) = {w ∈ A | proper prefix of w is a member of A}
- None of the above