2. When original plans are available, these must be used...

a.      to determine the color scheme of a building.

b.     to justify the removal of later additions.

c.     to justify the addition of a porch which was removed in the past.

d.     to return the building to its original state.

RIGHT !

Often changes are made to buildings over the years. If the owners want to return a building to its original state, as shown by old photographs, or the original architectural plans, this would definitely be allowed. But without the original plans, it would be difficult to justify tearing off an existing porch and adding an entirely different one.