There are six questions below，

In a benefit concert each of exactly seven solo performers—Harris, Jones, McIntyre, Nelson, Strapp, Trevino, and Williams—willsing. The concert director is deciding the order in which the performers will sing and is assigning each to exactly one ofseven time slots, numbered consecutively 1 through 7, according to the following conditions：

Harris mustsing atsome time before McIntyre sings. Strapp must sing at some time before Jones sings. Trevino must sing either immediately before or immediately after Nelson sings.immediately after Nelson sings. Williams must be assigned to time slot 3.

Which of the following could be the order, from first through seventh, in which the performers sing？

If there are exactly four performers who are to sing after Nelson sings but before Strapp sings, Harris must be assigned to time slot

If Williamsisto sing immediately after Harrissings and immediately before Trevino sings, which of the following performers could be assigned to time slot 6？

If Jones is to sing immediately before Harris sings, which of the following must be assigned to time slot 7？

If McIntyre is to sing immediately before Strapp sings, Trevino could be assigned to which of the following time slots？

If McIntyre is assigned to time slot 4, which of the following must be true？