A company produces and ships 16 personal computers knowing that four of them have defective wiring. Th e company that purchased the computers is going to thoroughly test three of the computers. Th e purchasing company can detect the defective wiring. What is the probability that the purchasing company will fi nd the following?

a. No defective computers

b. Exactly three defective computers

c. Two or more defective computers

d. One or no defective computers