Answer:
Option B is correct.
Unit rate = 0.40 km/min
Step-by-step explanation:
Given : A graph with a line running through coordinates (0,0) and coordinates (75, 30).
Here, y represents the distance traveled in km and x represents the number of minutes.
Find the slope of the line:
Slope(m)=
= 
Given points: (0, 0) and (75, 30)
then;
Since, unit rate is also the slope of the graph.
Therefore, unit rate(in km/min) = 0.40 km/min