In a jurisdiction where the use of headlights is optional when visibil

Even though I did not get the correct answer , but I would like to try explain the reason behind the correct answer (from my understanding).

btw, still waiting to read the OE and other's approach

Passage Given
In a jurisdiction where the use of headlights is optional when visibility is good,
➔saying about the fact that using headlights is optional choice.

drivers who use headlights at all times are less likely to be involved in a collision than are drivers who use headlights only when visibility is poor.
➔comparing chance of involing in a collision of 2 groups of people ,
when the visibility is poor 1) people who use headlights 2) people who does not use headlights

Conclusion drawn
Yet Highway Safety Department records show that making use of headlights mandatory at all times does nothing to reduce the overall number of collisions.
➔based on the records that making use of headlights mandatory at all times did not help reduce overall number of collisions

We can refer based on the given part+conclusion part that
1 At first the use of headlights in good visibility situation is optional.
2 Author continue to give another fact , Chance of involving in collisions w/headlights < w/o headlights
3 from passage we can infer that there is a change in regulations (from optional to use at all time)
4 However, despite the positive of headlights (lower chance of involving in collisions) ,after the change, total numbers of collisions still not reduce.

Prethink
What we have to think is why 1+2 and 3 are not pointing in the same direction ? , solve the paradox.
1 Maybe the main reason of collision is not because of less usage of headlights.
Maybe there are other reasons , such as seatbelts, speed, whether etc.
2 Maybe before the rules was implimented , drivers already use headlights.

(A) In jurisdictions where use of headlights is optional when visibility is good, one driver in four uses headlights for daytime driving in good weather.
X good weather is not given in the passage , the author did not use weather in his reason to approach the conclusion
X out of scope

(B) A law making use of headlights mandatory at all times is not especially difficult to enforce.
X passage did not address about how difficult to enforce the regulation
X out of scope

(C) Only very careful drivers use headlights when their use is not legally required.
✓ Along with the prethink 2, If most of the driver already use the headlight then the headlight regulation thing is not going to affect overall number of collision.

(D) There are some jurisdictions in which it is illegal to use headlights when visibility is good.
X seems opposite to the passage idea

(E) The jurisdictions where use of headlights is mandatory at all times are those where daytime visibility is frequently poor.
X did not written on the passage that this regulations is for specific group of people only

Hope this helps