The graph of d=t is equivalent to a graph of x=y. This becomes a straight line that rises 1 and runs 1. This eliminates choice 3.
The graph of d=-t+4 is equivalent to y=-x+4. This means that the y intercept is 4 which eliminates choice 2. A negative slope goes downhill from left to right which eliminates choice one. This leaves you with choice 3.
