Answer the question based on the information given below: A Musical band of six persons are to be selected from a group of six singers Bobby, Elvis, Joshua, Stephen, Phil and Jenny and six musicians - Helen, Sharon, Luke, Paul, Lisa and Kelly The band must be of exactly three singers. The band must be selected in such a way that the names of any two persons selected must not start with the same letter. It is also known that, (1) If Phil is not selected, Bobby must be selected. (2) If Helen is selected, Elvis must be selected. (3) Exactly one of Kelly and Sharon must be selected. If Bobby is not selected and Stephen is selected, who are the other singer/singers that is/are always selected?