Answer:
Graph (C)
Explanation:
If Bob traveled 'y' miles in 'x' hours,
Distance traveled ∝ Time taken to cover the distance
y ∝ x
y = mx
Here, m = proportionality constant Or slope of the line
Since, Bob covered 45 miles in 1.5 hours,
m =

m = 30 miles per hour
From the given graphs,
Graph (C) shows the slope =

=

= 30 miles per hour
Therefore, Graph (C) will show the relationship.