During Spirit Week, the band decided to have a bake sale every day of the seven day week. Three booth workers were appointed: a sophomore, a junior, and a senior. A very bright freshman made up a riddle about the work schedule. Here are the clues she made about who worked when:

1. On only one day of the week were all three students to help.

2. No student helped three days in a row.

3. No two students were off on the same day more than one time.

4. The sophomore was off on Sunday, Tuesday, and Thursday.

5. The junior was off on Thursday and Saturday.

6. The senior was off on Saturday.

On which day of the week were all three students working?