Hi, I am wondering if anyone could help me with this please. I am not sure which properties the following digital system displays

Question: Which of the following properties are exhibited by the digital system represented by

h[n] = r [4-n]u[n]?

Linearity, time- variance, causality stability and memory.

NB: r[n] is the ramp function and u[n] is the step function.

I am not sure how to work it out. sorry and thanks