How many permutations are there of 42 objects when taken 9 objects at a time, if a particular one of these objects must always b included? O a. 9(42)/(42-9)! b. 9(42-1)/(42-9-1)! O c. 9(42-1)/(42-9)! d. 42(42 1)/(42-9-2)! e. (42-1)/(42-9-2)!