Hi! It is my understanding that the tenor part can range anywhere the from the C below middle C to the G above middle C. There are some general rules between the parts - for instance, the alto and tenor parts should not cross each other for extended periods of time, etc. However, when it comes to the specific note that the tenor is singing, it will vary between the root note, 3rd, 5th, 7th, or any other note as arranged.
