Multi-select problem: How does the next paragraph end?

How to smoke in your house without people knowing
Open a window or fireplace duct.
Before you start smoking, it's very important you give the smoke an exit to escape. Without an open window or duct, the smoke will linger in the room and your health will be at risk.

OPTIONS:
[1]. If somebody walks in while you're smoking, make sure a window isn't visible. Light up a fire for a few minutes, or just shut the window or fireplace, in case anyone comes into view.
[2]. Open any blinds, curtains, or any natural curtains you use inside. Hide under couches, chairs, or anything else that can reflect light.
[3]. If there are doors leading to other rooms, use them to let the smoke escape. Put smoke blocks, cardboard boxes, or put glass flammable objects on fire.
[4]. Depending on the room you're going to smoke in, there should almost always be some window to open. A fireplace duct is an even better choice, as fireplaces are specifically designed to let smoke escape.
[4].