For drivers 18 years of age and older, texting while driving is considered what kind of offense?

Answer: B — Secondary offense

Texting while driving, for drivers 18 years and older, is considered a secondary offense. This means that it is not illegal on its own, but can result in a fine or citation if the driver is pulled over for another offense. Option A, primary offense, is incorrect because primary offenses are violations that can result in immediate legal action without needing another reason for the traffic stop. Option C, tertiary offense, is incorrect because tertiary offenses are less serious violations that often result in a smaller fine or citation. Option D, not an offense, is incorrect because texting while driving is against the law in many places and can result in legal consequences.