Like chess or painting or writing novels, making money is a very specialized skill but is now treated not equally as playing chess or painting or writing novels.

A．TV stations always operate at the highest sound levels
B．their sound levels are kept around peak levels
C．their sound levels are kept in the middle frequency ranges
D．unlike regular programs their intensity of sound varies over a wide range

A．the human voices in commercials have more auditory impact
B．people like cheerful songs that change dramatically in sound quality
C．high-frequency sounds are used to mask sounds that drown out the primary message
D．they possess sound qualities that make the viewer feel that something unusual is happening