What is the best way to: How do you prepare an iron for use for ironing a muslin photography backdrop?

Choices:
a). Fill the water reservoir of the iron up to the fill line with filtered water. Plug the iron into a nearby wall outlet. Turn the iron on. Set the iron to the cotton setting and allow it to heat up for approximately five minutes..
b). Fill the water reservoir of the iron up to the fill line with filtered water. Plug the iron into a nearby wall outlet. Turn the iron on. Set the iron to the silk setting and allow it to heat up for approximately five minutes..
Answer:
a).