This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to buy a hot tub
Decide where to put your hot tub.
People install 90 percent of all hot tubs outside on a patio or deck. Of the 10 percent installed inside a home, most go in the master suite, an enclosed sun room or a finished basement.

Choices:
(I) Measure the hot tub area to ensure a comfortable fit. Be sure to allow enough room for getting in and out of the tub..
(II) Additionally, most hot tubs can also be used inside your garage, as long as the windows and doors are shut and there is no smoke in the garage. Decide on a location for your hot tub that falls within a particular environmental level..
(III) Each person can move the hot tub outside and leave the other 10 percent inside a hallway or a converted garage and they will want to be safe and not be teased by parents. Find out where your tub is supposed to be..
(IV) However, another quarter may also take place outdoors at other places in the world. If you live in an area where hot tubs occur, make sure to research what hot tubs are used in your area..
The answer is:
(I)