Cytochrome oxidase is an example of which of the following?

The correct option is B Endoenzyme
In mitochondrial electron transport system, complex IV also called as cytochrome oxidase, contains cytochrome a and a3. These cytochromes consist of two haeme groups bound to different regions of the same large protein that are therefore spectrally and functionally distinct. Cytochrome oxidase also contains two copper ions copper a and copper b that are crucial to the transfer of electrons to oxygen. This complex enzyme has evolved to carry out the four electron reduction of oxygen without generating the incompletely reduced intermediates such as hydrogen peroxide or hydroxyl free radicals which are very reactive species that would damage cellular components.