For each of the following, indicate whether the type of probability involved is an example of a priori probability, empirical probability, or subjective probability.

a. The next child born in the Walton family will be a boy.

b. The next Nobel Prize for Literature will be awarded to someone from Africa.

c. The sum of numbers when rolling two fair dice will be 9.

d. The plane flying to deliver medical supplies will be early by more than 15 minutes.