The county ___ collects real estate taxes.

The county treasurer is responsible for collecting real estate taxes. The treasurer's office manages the financial transactions of the county, which includes the collection of various taxes, such as property taxes. This role typically involves not only collecting the taxes but also handling other aspects of county funds, ensuring they are properly allocated and disbursed according to local government regulations.

The assessor's role primarily involves determining the value of properties for tax purposes, while the clerk usually handles official records and documentation, including property deeds and court documents. The auditor's function often revolves around financial oversight and ensuring the accuracy of the county's financial statements but does not typically include the direct collection of taxes. Therefore, the treasurer is specifically tasked with the important duty of collecting real estate taxes, making this the correct choice.