Final answer:
The human resources department is most likely responsible for approving changes in pay rates and deductions from employee salaries, as these are core HR functions.
Step-by-step explanation:
The department or position most likely to approve changes in pay rates and deductions from employee salaries is human resources (HR). The HR department is typically responsible for managing the employment process, which includes setting pay rates, managing benefits, and handling deductions like taxes and other payroll-related items. The payroll department manages the process of paying employees, which includes calculating earnings and deductions, but changes to these rates would generally require authorization from HR.
The controller oversees the accounting operations, which may include payroll, but their main function is to ensure the accuracy and integrity of financial reporting. The treasurer manages the organization's finances, but they are not usually involved in setting salaries or specific deductions. While the payroll department implements payroll processing, it typically does not have the authority to approve changes in pay rates; this department acts on the directions of HR.