Select the sentence from the section "An Ultracool Dwarf" that BEST explains what TRAPPIST-1 is.
Group of answer choices

Current observations suggest its orbital period could range anywhere from four to 73 days.

The star is just .05 percent as bright as our sun.

The system’s host star, called TRAPPIST-1, is what is known as an ultracool dwarf.

It is about one-tenth the size of our sun and just a bit bigger than Jupiter.