Classify each of the following random variables as either continuous or discrete:
a. The survival time of a cancer patient after receiving a new treatment for cancer
b. The number of ticks found on a cow entering an inspection station
c. The average rainfall during August in College Station, Texas
d. The daily dose level of medication prescribed to a patient having an iron deficiency
e. The number of touchdowns thrown during an NFL game
f. The number of monthly shutdowns of the sewage treatment plant in a large Midwestern city.