Which of the following demonstrates the law of inclusion-exclusion applied to find the probability that in two coin flips, at least one heads occurs?
A. P(at least one head)=P(first throw is a head)+P(second throw is a head)
B. P(at least one head)=P(first throw is a head)+P(second throw is a head)−P(both throws are heads)
C. P(at least one head)=P(first throw is a head)+P(second throw is a head)+P(both throws are heads)