The thing to notice here is that every even number has a 2 in it. You can pull all these 2s to the front of the number, which turns a sequence of consecutive evens like this into a string of consecutive numbers (evens and odds).
From here, you can see where the larger prime factor is.
For every even positive integer m, f(m) represents the product of all even integers from 2 to m, inclusive. For example, f(12) = 2 x 4 x 6 x 8 x 10 x 12. What is the greatest prime factor of f(24) ?
(A) 23
(B) 19
(C) 17
(D) 13
(E) 11
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