What is the unit rate, expressed in kilometers per minute?

0.25 km/min

0.40 km/min

1.50 km/min

2.50 km/min

The answer is:  [B]:  0.40 km/min .

Explanation:

From the graph attached, which is "linear", we have 75 minutes (x-axis);
                 corresponding to 30 km (y-axis);

 We notice that all the answer choices are given in units of:
 
                   →    "km/min" ;   that is, "kilometers per minute" ;

 →  So, 30 km / 75 min  = (30/75) km/ min = ? km / min ; 

       →  (30/75) = (30÷15) / (75÷15) = ⅖  km/min ; or 0.4 km/min ;

       → or; use calculator: (30/75) = (30÷75) = 0.4 km/min ;

                →   which corresponds to: 

                          →  Answer choice:  [B]:  0.40 km/min .