How would the pattern in the last question be different if instead of one slit, there were two slits, each $0\mathrm{.}02$mm wide, separated by $0\mathrm{.}4$mm $($instead of $0\mathrm{.}2$mm$).$ Again assume that the slits are vertical.

The big envelope becomes wider, so that more of the small lines fit within it$.$

The thinnest lines would be half the distance apart, so there are more of them in each big envelope.$$

Nothing changes: the same amount of light comes through the slits.$$

The big envelope becomes narrower, so that fewer of the small lines fit within it$.$

The thinest lines would be twice as far apart, so there are fewer of them in each big one.