Cystic fibrosis is a hereditary disorder caused by a recessive mutation. In a previous marriage, Jim had a child with cystic fibrosis, though neither Jim nor his first wife had the disease. Jim is now married to Martha. No one in Martha’s family (including her parents, grandparents, and other relative) is afflicted with cystic fibrosis. What is the probability that Jim and Martha will have a baby who is a carrier of cystic fibrosis?
which one ?