A manufacturer of headache medicine claims it is 70% effective within a few minutes. That is, out of every 100 users, 70 get relief quickly. A group of 12 patients are given the medicine. If the claim is true, what is the probability that 8 have relief in a few minutes?
a. 0.001
b. 0.168
c. 0.667
d. 0.231
e. None of the above