Decide whether each of the following characteristics of a television news broadcast is a continuous or discrete random variable:
a. Number of commercials shown (e.g., five commercials).
b. Length of the first commercial shown (e.g., 15 seconds).
c. Whether there were any fatal car accidents reported (0 = there were no fatal accidents reported, 1 = there was at least one fatal accident reported).
d. Whether rain was forecast for the next day (0 = no rain forecast, 1 = rain forecast).