The probability that all four people are AB is (0.03) 4 * (1-0.03);

The probability that all three people are AB is (0.03) 3 * (1-0.03) 2;

The probability that two people are AB is (0.03) 2 * (1-0.03) 3;

The probability that a person is all AB is (0.03) * (1-0.03) 4;

Then the probability that no one is AB is (1- above).