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)\;and\;h_1(t) $