Official Solution:If \(n\) is a positive integer, what is the units digit of \(4^n\)? The units digit of \(4^1\) is 4.
The units digit of \(4^2\) is 6.
The units digit of \(4^3\) is again 4.
The units digit of \(4^4\) is again 6.
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From the pattern, we can deduce that if \(n\) is a positive odd number, the units digit of \(4^n\) is 4. If \(n\) is a positive even number, the unit's digit of \(4^n\) is 6. Therefore, to answer the question, we need to determine whether \(n\) is odd or even.
(1) \(n^2\) is divisible by 4.
Since it is given that \(n\) is an integer, for \(n^2\) to be divisible by 4, \(n\) must be even. Sufficient.
(2) \(n+2\) is divisible by 6.
This statement implies that \(n+2\) is even, which means \(n\) is also even. Sufficient.
Answer: D