First, we recognize that,
Any positive integer, N, can be represented as a multiple of it's prime factors to some power
\(N = P^a*Q^b*R^c\), where P,Q,R are prime numbers, and a,b,c are their respective powers
\(# of factors of N = (a+1)*(b+1)*(c+1)\)
Now, we are given that "n" has 24 positive factors and we need to find the RANGE of the # of prime factors that "n" can have,
We can write the 24 factors of "n", as \(P^2^3\), and we will get 24 positive factors -----> Note in this case we only have 1 prime factor, P
To find the maximum number of prime factors, we need to split 24 into the maximum number of its factors,
It can be written as, \(24 = 2*2*2*3\),
which means "n" can be written as \(P^1*Q^1*R^1*S^2\) ------> In this case, we have 4 different prime factors, P,Q,R, and S
So to caluclate the range of the # of prime factors, we have 4 - 1 = 3
So, the answer is C.