Question

A code is formed using four of these letters: A, B, I, K, N, O, and T. (Note that the order of the letters in the code matters; for example, ABIK is a different code from BAIK. )
The size of the sample space is 1.)_________. The probability that the first three letters of the four-letter code are vowels is 2.)_________.
1.)
A.120
B.360
C.840
D.1680

2.)
A.1/35
B.1/60
C.1/140
D.101/105