Let $A,D \in \mathbb{R}^{n\times n}$ be two positive definite matrices given by

$$
D =
\begin{bmatrix}
2 & -1 & 0 & 0 & \dots & 0\\
-1 & 2 & -1 & 0 & \dots & 0\\
0 & -1 & 2 & -1 & \dots & 0\\
\vdots & \ddots & \ddots & \ddots & \ddots & 0\\
0 & \dots & 0 & -1 & 2 & -1\\
0 & 0 & \dots & 0 & -1 & 2
\end{bmatrix}, \quad
A =
\begin{bmatrix}
2 c_{1,1} & -c_{1,2} & 0 & 0 & \dots & 0\\
-c_{2,1} & 2 c_{2,2} & -c_{2,3} & 0 & \dots & 0\\
0 & -c_{3,2} & 2 c_{3,3} & -c_{3,4} & \dots & 0\\
\vdots & \ddots & \ddots & \ddots & \ddots & 0\\
0 & \dots & 0 & -c_{n-1,n-2} & 2 c_{n-1,n-1} & -c_{n-1,n}\\
0 & 0 & \dots & 0 & -c_{n,n-1} & 2 c_{n,n}
\end{bmatrix}
$$
with $c_{i,j} \in (0,c_+]$ for all $i,j=1,\dots,n$ for a $c_+ \in (0,\infty)$.

I would like to prove that independent of the dimension of $n$
$$x^\top A x \le c_+ x^\top D x$$
holds for all $x\in \mathbb{R}^n$.
If this is not the case does there exist a counter example?

This is somehow related to that the norms of the induced scalar products of the matrices $A$ and $D$ are equivalent with factor $c_+$.