One of the electron ultimately ends up reducing the copper B, and the other electron ultimately ends up reducing the heme A three. So this should be the heme A three. And so we summarize this step in the following way. So, we have two reduced cytochrome C molecules give off a total of two electrons. So one electron per cytochrome C molecule. One of the electron stops at the copper B group, reducing it, as discussed here, and the other basically stops at the heme A three, reducing that heme A three.