To find the greatest integer k for which 3^k is a factor of p, we need to determine how many times 3 appears as a factor in the product of the integers from 1 to 30.
Since we are looking for the number of times 3 appears as a factor, we can count the number of multiples of 3 among the integers from 1 to 30.
There are 10 multiples of 3 between 1 and 30, namely: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30.
However, among these multiples, there are additional factors of 3 in numbers such as 9 and 27, which have multiple factors of 3.
So, let's count the total number of factors of 3 among the multiples of 3 between 1 and 30:
3 (1 factor of 3)
6 (1 factor of 3)
9 (2 factors of 3)
12 (1 factor of 3)
15 (1 factor of 3)
18 (2 factors of 3)
21 (1 factor of 3)
24 (1 factor of 3)
27 (3 factors of 3)
30 (1 factor of 3)
Adding up the total number of factors of 3, we have 1+1+2+1+1+2+1+1+3+1=14.
Therefore, the greatest integer k for which 3^k is a factor of p is k=14.
The correct answer is (C) 14.