Consider a discrete-time LTI system with impulse response given by h[n] = [n + 1] ???? 2[n] + [n ???? 1] where [n] is the unit impulse (or unit sample) function. (a) Is this system causal? (b) Is this system stable? (c) Find and sketch the step response of this system|i.e., the output when the input is a unit step.