3. Given the ellipse $C: \frac{x^{2}}{8}+\frac{y^{2}}{4}=1$. For any real number $k$, the length of the chord intercepted by the ellipse $C$ from the following lines cannot be equal to the length of the chord intercepted by the line $l: y=k x+1$ is ( ).
(A) $k x+y+k=0$
(B) $k x-y-1=0$
(C) $k x+y-k=0$
(D) $k x+y-2=0$
3. D.

For option (A), when $k=1$, the chord length of the ellipse $C$ intercepted by the line $k x+y+k=0$ is equal to the chord length intercepted by $l$;

For option (B), when $k=0$, the chord length of the ellipse $C$ intercepted by the line $k x-y-1=0$ is equal to the chord length intercepted by $l$;

For option (C), when $k=-1$, the chord length of the ellipse $C$ intercepted by the line $k x+y-k=0$ is equal to the chord length intercepted by $l$.