The first one is a little tricky, but not that hard if we just think about it
The total perimeter = 2 (70 + 50) = 2 * 120 = 240 m
The point (0, 0) is one point on the graph.....at 0 minutes we have walked 0 m !!!
Also.....if the person walks for three minutes......he has walked 3(80m) = 240 m = 1 round
So....he has made 1 round in 3 minutes
So....the point ( 3,1) should be on the graph
So.....the graph at the bottom left is the correct one
Note that after 6 minutes, we have made 2 rounds
So.....(6,2) is also on the graph