Determine whether the probabilities below are computed using the classical method, empirical method, or subjective method.

(a) The probability of having six girls in a six-child family is 0.015625.

(b) On the basis of a survey of 1000 families with six children, the probability of a family having six girls is 0.0069.

(c) According to a sports analyst, the probability that a football team will win the next game is 0.31.

(d) On the basis of clinical trials, the probability of efficacy of a new drug is 0.84.