Please do the "a". Thanks!

1.40 Recall 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. In each of the following parts, we define an operation on a language A. Show that the class of regular languages is closed under that operation. Aa. NOPREFIX (A)-(w Al f A} no proper prefix of w 1s a member o