The cumene process is used to convert benzene and propene in the presence of oxygen to phenol and acetone via the reaction C₆H₆ + C₃H₆ + O₂ = C₆H₅OH + C₃H₆O. This reaction is carried out with excess:
a) C₆H₆
b) C₃H₆
c) O₂
d) C₆H₅OH