Cho $k,n\left( {k < n} \right)$ là các số nguyên dương. Mệnh đề nào sau đây sai ?
![](https://m.moon.vn/Images/Teachers/nguyenoanh8892/To%C3%A1n/04/1/1.png)
A.
![](https://m.moon.vn/Images/Teachers/nguyenoanh8892/To%C3%A1n/04/1/1a.png)
B.
![](https://m.moon.vn/Images/Teachers/nguyenoanh8892/To%C3%A1n/04/1/1b.png)
C.
![](https://m.moon.vn/Images/Teachers/nguyenoanh8892/To%C3%A1n/04/1/1c.png)
D.
![](https://m.moon.vn/Images/Teachers/nguyenoanh8892/To%C3%A1n/04/1/1d.png)
Đáp án B
![](https://m.moon.vn/Images/Teachers/nguyenoanh8892/To%C3%A1n/04/1/1e.png)