Cytochromes are found in

• matrix of mitochondria

• outer wall of mitochondria

• cristae of mitochondria

• lysosomes

C.

cristae of mitochondria

Cytochromes are present on the cristate, i.e. inner foldings of mitochondria. Cytochromes are iron (heme) containing proteins primarily responsible for transfer of electrons in ETC from ubiquinone to complex-V for generation of ATP(energy molecules) and terminal acceptor O₂ in electron transport chain.
They are also called respiratory pigments, which are capable of performing both the oxidation and reduction reactions.