Which of the following is correct and most complete?

a. Random variables are numbers whose values are known at time of planning.

b. Probabilities can generally be written as expected values of indicator functions.

c. Probability theory and simulation can generate information of interest to people considering which methods or strategies to apply.

d. mod(9,7) = 2.

e. All of the above are correct.

f. All of the above are correct except

(a) and (e).