5. In the plane of equilateral $\triangle A B C$, the condition that line $m$ satisfies is: the distances from the 3 vertices of equilateral $\triangle A B C$ to line $m$ take only 2 values, and one of these values is twice the other. The number of such lines $m$ is ( ).
(A) 16
(B) 18
(C) 24
(D) 27
5.C.

As shown in Figure 4, there are a total of $8 \times 3=24$ lines.