Read the text and determine if the sentence is true (see options at the end):

There have been four head coaches of the Houston Texans, a professional American football team based in Houston, Texas, United States. The Texans play in the South Division of the American Football Conference (AFC) in the National Football League (NFL).

Sentence: All four of the head coaches are former head coaches.
 a). Yes; b). It's impossible to say; c). No;
b).