If \(10^n + 3\cdot 4^{\,n+2} + k\) is divisible by 9 for all \(n \in \mathbb{N}\), then the least positive integral value of \(k\) is
5
3
7
1
For all \(n \in \mathbb{N}\), \(3\cdot 5^{2n+1} + 2^{3n+1}\) is divisible by
19
17
23
25
If \(x^n - 1\) is divisible by \(x - k\), then the least positive integral value of \(k\) is
1
2
3
4