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?
1
NOPREFIX(A) = {ω Є A | no proper prefix of ω is a member of A}
2
EXTEND(A) = {ω Є A | ω is the proper prefix of any string in A}
3
PREFIX(A) = {ω Є A | proper prefix of ω is a member of A}
4
None of the above
5
Question Not Attempted