A Nielsen Rating of 15

A Nielsen rating of 15.3 for a CSI television show means:

A) 15.3 percent of viewers of CSI watched the ads during the show.
B) of the televisions that were turned on in the U.S., 15.3 percent were tuned to the CSI show.
C) 15.3 percent of all televisions in the U.S. were tuned to the CSI show.
D) of those watching the CSI show, 15.3 percent matched the advertisers target market.