Write the next sentence in the following story.

How to meditate deeply
Choose a space in your house that is quiet.
Picking a room with a door, away from areas with children or traffic would be best.
Find a straight-backed chair or floor cushion.

Pick from:
[a]. It shouldn't be squishy or soft. The cushions will carry your weight all the way across and are what help you do your meditation.
[b]. The ideal seat is not so comfortable that you can fall asleep, but adequately comfortable to sit in for at least 20 or 30 minutes. Light the space with soft natural light.
[c]. Having a supportive chair is important, as it allows the head to stay balanced without stiff legs. Place the incense sticks on a low desk or windowsill with minimal stress.
[d]. A table or a bookcase work well. Sit down with your back straight and your knees spread.. The answer should be
[b].