In the equation \( 25h + 10 \), where \( h \) represents the number of hours Sarah babysits, the term \( 25h \) indicates the amount of money she earns based on her hourly rate. Specifically, the number \( 25 \) represents the amount of money she charges per hour to babysit.
Therefore, the correct answer is:
The amount of money she charges per hour to babysit.