The correct answer is option a) "They wanted to give advertisers a better chance of reaching their target audiences.". Radio stations such as the one of NBC must always look to attract advertisers in order to get money and stay on the air. By running different types of contents on different stations, NBC divides their audience in different target audiences, which is very attractive to advertisers as they could reach potential new customers more easily.
Intolerant means not being able to accept differences in opinions or other ideas, or someone who is unable to handle something. This includes being unable to endure something.
