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 $h_1$(t)
* *and $h_2$(t)*.*