Which change to one of the kits would make it useful for modeling proteins? a.Set 1, add a box for phosphorous (P) atoms. b.Set 2, add a box for sulfur (S) atoms c.Set 3, replace the box of phosphorous (P) atoms with a box of sulfur (S) atoms d.Set 4, replace the box of oxygen (O) atoms with a box of nitrogen atoms (N)