Q4

The diagram shows the graphs of the functions $f(x)$ and $g(x)$.

It is known that

$$\begin{aligned} \int_a^c f(x)\,dx&=10,\\ \int_a^b g(x)\,dx&=-2,\\ \int_b^c g(x)\,dx&=3. \end{aligned}$$

What is the area between the curves $y=f(x)$ and $y=g(x)$ between $x=a$ and $x=c$?
A. $5$
B. $7$
C. $9$
D. $11$