Final answer:
The correct answer is 3) providing security at airports. Operating the county jail, serving as officers of the court, and contracting to provide traffic and criminal investigations for small towns are all major responsibilities for a sheriff's department.
Step-by-step explanation:
The correct answer is 3) providing security at airports. Operating the county jail, serving as officers of the court, and contracting to provide traffic and criminal investigations for small towns are all major responsibilities for a sheriff's department. However, providing security at airports is not typically a responsibility of a sheriff's department.