C

In the picture there are two parabolas. One parabola can be mapped onto the other by shifting. These parabolas are graphs of the quadratic functions $$f(x)=-(x-a{)}^2+b\text{ and }g(x)=-(x-c{)}^2+d,$$ where $a$, $b$, $c$, $d\in \mathbb{R}$. Following statements describe the relations between the pairs of the coefficients $a$, $b$, $c$ and $d$. Choose the true statement.