Answer:
The car furthest from the finish line: Car III (Choice C).
Explanation:
It's asking for lowest average speed throughout the entire race. Therefore, whoever is last technically has the lowest average speed.
Car III is far behind Car I and Car II so Choice A and B aren't correct. Choice D is incorrect since the three cars aren't in the same position. Choice E is incorrect because there is enough information to see that Choice C has the lowest average speed.