The definition of impulse is
$\begin{align*}\mathbf{J} := \int_{t_1}^{t_2} \mathbf{F} dt\end{align*}$
So, the impulse is the area under the curve. The area of each triangle is $1 \mbox{ N s}$ , so the total impulse delivered to the particle is $\boxed{2 \mbox{ N s}}$ . Therefore, answer (C) is correct.

Solution to 2001 Problem 54