If h1, h2 and h3 are cascaded, and h1 = u(t), h2 = exp(t) and h3 = sin(t), find the overall impulse response

• A. sin(t)*exp(t)*u(t)
• B. sin(t) + exp(t) + u(t)
• C. u(t)*sin(t)
• D. all of the mentioned