Schools have six low-emitting materials credits, but can earn a maximum of four points from them, so choose four to pursue: 

Choose the credits that are the easiest for your project to achieve. Typically IEQc4.1 and IEQc4.2 are the easiest.  IEQc4.3, IEQc4.4, and IEQc4.5 can be more difficult or expensive to achieve.