An experienced golf player is participating in a tournament at a golf course that has three types of holes: Penal, Heroic and Detour. The course has 4 holes that are type Penal, 5 are type Heroic and 9 are type Detour. The player is able to complete each type on average using 5, 4 and 6 strokes respectively. What is the standard deviation for the number of strokes that the player will use to complete the course? (Round to 2 decimal places). a 0.77 . b. 0.73 c. 0.85 d. 0.89 e. 0.84