An online form has a "Title" input field. The valid values for this field are: Mr, Ms, Mrs. Which of the following is a correct list of the equivalence classes of the input values for this field?
A. Any one of: Mr, Mrs., Ms; any other input
B. Mr; Ms; Mrs.; no input; any other input
C. Any one of: Mr, Mrs., Ms; no input; any other input
D. Mr, Mrs., Ms; any other input
Is it not B ?