premise: A chemistry class has six lab sessions scheduled over three days—Wednesday, Thursday, and Friday—one session heing held each morning and one each afternoon. Each session will be led by a different lab assistant—Julio, Kevin, Lan, Nessa, Olivia, or Rebecca. The assignment of lab assistants to sessions is constrained as follows: Kevin and Rebecca must lead sessions that meet on the same day. Lan and Olivia cannot lead sessions that meet on the same day. Nessa must lead an afternoon session. Julio's session must meet on an earlier day of the week than Olivia's. If Kevin's session meets on the day before Nessa's, then which one of the following is a complete and accurate list of lab assistants any one of whom could lead the Thursday afternoon session?
hypothesis: Kevin, Nessa, Rebecca