I know nothing about a footprint of a house . . . what is it?
I Have A Footprint Of A House.
And There Are 7 Options That Could Change That Footprint.
So How Many Footprints Can There Be Total?
For each option, there are two choices: apply it or don't apply it.
Hence, there are: possible options
. . from "use none of them" to "use all of them".