5. As shown in Figure 1, hexagon $A B C D E F$ is composed of five unit squares. A line that can bisect the area of this hexagon is called a "good line". Then the number of good lines is ( ) lines.
(A) 1
(B) 2
(C) 3
(D) infinitely many
5. D.

Let the midpoint of $CD$ be $H$, and the centers of rectangle $ABCH$ and rectangle $EFHD$ be $O_{1}$ and $O_{2}$, respectively. Then $O_{1}O_{2}$ is a good line, and any line passing through the midpoint $M$ of segment $\mathrm{O}_{1} \mathrm{O}_{2}$ (intersecting segment $DE$) is also a good line.