Two systems with impulse responses $h_1(t)$ and $h_2(t)$ are connected in cascade.then the overall impulse response of the cascaded system is given by
- Product of $h_1(t)$ and $h_2(t)$
- Sum of $h_1(t)$ and $h_2(t)$
- convolution of $h_1(t)$ and $h_2(t)$
- subtraction of $h_2(t)$ from $h_1(t)$