The U. S. Constitution requires that the president should be a ______ -year-old native born American citizen, living in the States for 14 years.

A．the process of specialization and professionalisation
B．the hardship of amateurs in scientific study
C．the change of policies in scientific publications
D．the discrimination of professionals against amateurs

A．sociology end chemistry
B．physics and psychology
C．sociology and psychology
D．physics and chemistry