Step 1 :Analyze the given options for the meaning of the phrase 'over-driving headlights':
Step 2 :a. the headlights are out of adjustment because they are aimed too low
Step 3 :b. the headlights are out of adjustment because they are aimed too high
Step 4 :c. inability to stop within the distance illuminated by the headlights
Step 5 :d. you have been driving with your headlights on for an extended period of time
Step 6 :Choose the most appropriate option, which is c. inability to stop within the distance illuminated by the headlights
Step 7 :\(\boxed{\text{c. inability to stop within the distance illuminated by the headlights}}\)