premise: A concert promoter is filling the six slots at a benefit concert. The slots, from earliest to latest, are numbered slot one through slot six. The slots will be filled by six bands—Uneasy, Vegemite, Wellspring, Xpert, Yardsign, and Zircon. Each band will perform in just one slot. The order must meet the following constraints: Vegemite performs in an earlier slot than Zircon. Wellspring and Zircon each perform in an earlier slot than Xpert. Uneasy performs in one of the last three slots. Yardsign performs in one of the first three slots. If Wellspring performs immediately before Xpert, which one of the following could be true?
hypothesis: Zircon performs in slot four.