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

How to buy an air conditioner
Shop for an air conditioner in the cooler months.
Many brands are more likely to be on sale and in stock.
Decide between a window, portable or wall air conditioning unit.

Choose your answer from:
[1]. Many retail air conditioners can grow to be portable. See the specs section below to get a great idea of how much air these units need to keep cool..
[2]. These options will definitely not be necessarily for you, but will make almost any air conditioner an asset. Decide how much air you are willing to invest..
[3]. Unlike window units, portable units do not need to be mounted in a window. They are usually on wheels and are vented through a hose placed in a window..
[4]. Limit the part windows that have sheets on them. Ensure the replacement unit is compatible with your vehicle..
The answer is:
[3].