In order to determine automobile insurance premiums for a driver, insurance companies calculate various risk factors; as the risk factors increase, so does the premium.
Conclusion (should)
Insurance premiums should also increase with how often a person drives.
Evidence (After all)
A person's chance of being in a mishap rises in proportion to the number of times that person drives.
Evaluate
Whenever we do Main Conclusion / Role, we know they want to make it harder to find the conclusion, which they usually do by writing an Upside Down argument where the conclusion precedes its supporting evidence. 65% of them, the Conclusion is some Pivot / Rebuttal claim. 25% of them, the Conclusion is in the first sentence.
The first two sentences here seem factual and unsupported. They're just describing how insurance companies do their thang.
Then we get hit with a PIVOT (yet) and an OPINION indicator (should). That would immediately make us suspect a conclusion. Is this claim being Supported? Yes! It's followed by after all, which always indicates support.
Goal
We're being asked about the 3rd sentence, which was our main conclusion, so let's go look for an answer saying that the role is plays is Main Conclusion!