The number of positive integer solutions for the equation x +y +z + t = 30 is
Choose the correct choice from the following:
A) 3854
B) 3654
C) 3764
D) 3960
E) 4964

Rationale: "the number of positive integer solutions for the equatio fx 1 + x 2 + ⋯ + xn = k ( k - 1 ) c ( n - 1 ) - where k is the number and n is number of variable in the equation . 30 - 1 c 4 - 1 = 29 c 3 = 3654 answer : b"
Answer: B