5. (10 points) Figure $ABCD$ is a parallelogram, $M$ is the midpoint of $DC$, $E$ and $F$ are on $AB$ and $AD$ respectively, and $EF$ is parallel to $BD$. If the area of triangle $MDF$ is 5 square centimeters, then the area of triangle $CEB$ is ( ) square centimeters.
A. 5
B. 10
C. 15
D. 20
【Analysis】Connect $F C, D E, F B$, in trapezoid $F B C D$, $S_{\triangle F D B}$ and $S_{\triangle F D C}$ have the same base and height, so their areas are equal; in trapezoid $E B C D$, $S_{\triangle E D B}$ and $S_{\triangle E B C}$ have the same base and height, so their areas are equal; in trapezoid $F E B D$, $S_{\triangle F D B}$ and $S_{\triangle E D B}$ have the same base and height, so their areas are equal; therefore, $S_{\triangle F D C}=S_{\triangle E B C}$. Since $M$ is the midpoint of $D C$, according to the property that the area of a triangle is proportional to its base when the height is constant, $S_{\triangle E B C}=2 \times 5=10 \mathrm{~cm}^{2}$.

【Solution】Solution: As shown in the figure, connect $F C, D E, F B$,
In trapezoid $F B C D$, $S_{\triangle F D B}=S_{\triangle F D C}$,
In trapezoid $E B C D$, $S_{\triangle E D B}=S_{\triangle E B C}$,
In trapezoid $F E B D$, $S_{\triangle F D B}=S_{\triangle E D B}$,
Therefore, $S_{\triangle F D C}=S_{\triangle E B C}$,
Since $M$ is the midpoint of $D C$,
So $S_{\triangle E B C}=2 \times 5=10$ (square centimeters).
Thus, $S_{\triangle E B C}=10$ square centimeters,
Answer: The area of triangle $E B C$ is 10 square centimeters.
Therefore, the correct choice is: B.