Which statement is true about the code below?

$1$: #include

$2$: using namespace std;

$3$:

$4$: class Car $\{$

$5$: void doSomething$()\{$

$6$: cout $<<$ "drive" $<<$ endl;

$7$: $\}$

$8$: $\}$;

$9$:

$10$: class Horse $\{$

$11$: void doSomething$()\{$

$12$: cout $<<$ "run" $<<$ endl;

$13$: $\}$

$14$: $\}$;

$15$:

$16$: class Mustang : public Car, public Horse $\{$

$17$:

$18$: $\}$;

$19$:

$20$: int main $()\{$

$21$: Mustang m;

$22$: m$.$doSomething$()$;

$23$: $\}$