Consider the signal $x(t)$ shown in the figure. Let $h(t)$ denote the impulse response of the filter matched to $x(t)$, with $h(t)$ being non-zero only in the interval 0 to $4 \; \mathrm{sec}$. The slope of $h(t)$ in the interval $3 < t < \text{sec}.$ is
- $\frac{1}{2} \sec ^{-1}$
- $-1 \sec ^{-1}$
- $-\frac{1}{2} \sec ^{-1}$
- $1 \; \mathrm{sec}^{-1}$