What is the difference between A-Weighted and C-Weighted acoustic measurements?

A.
A-Weighted is the ambient sound pressure level; C-Weighted is the calculated sound pressure level.

B.
A-Weighted is sound a human can hear; C-Weighted includes levels out of human hearing range.

C.
A-Weighted is the average dB of a certain area; C-Weighted is a single measurement

D.
A-Weighted is the average dB of a certain area; C-Weighted is a combined total measurement.