A wildlife biologist is studying turtles that have been exposed to oil spills in the Gulf of Mexico. Previous studies have determined that a particular blood disorder occurs in turtles exposed for a length of time to oil at a rate of 1 in every 8 exposed turtles. The biologist examines 12 turtles exposed for a considerable period of time to oil. If the rate of occurrence of the blood disorder has not changed, what is the probability of each of the following events? She finds the disorder in:

a. none of the 12 turtles.
b. at least 2 of the 12 turtles.
c. no more than 4 turtles.