If the product of all positive divisors of the natural number N is equal to n4, then N is called a "good number", and the number of good numbers within 1999 and not divisible by 2,3,5 is (

1 is a good number,

Let n=abc(a, B and C are prime numbers),

∴n All positive divisors are: 1, A, B, C, ab, ac, bc, abc,

∴ 1×a×b×c×ab×ac×bc×abc=(abc)4=n4，

The product of all positive divisors of natural number n is equal to n4.

∴n is the product of three prime numbers,

* Not divisible by 2, 3, 5,

The prime numbers are: 7, 1 1, 13, 17,19,23,29. ...

Those that meet the requirements are: 90 1 = 7× 1 13,1001= 7×17. 177 1=7× 1 1×23, 1547=7× 13× 17, 1729=7× 13× 19.

Good numbers in the range of ∴ 1999 that are not divisible by 2,3,5 are: 1, 90 1, 100 1, 1463, 1.

So choose a.