Automated testing is ideal for scenarios involving repetitive tasks over extended periods. Here's why:  

Efficiency: Automated tests can execute tasks much faster than humans.  

Consistency: Automated tests perform the same steps precisely every time, eliminating human error.  

Endurance: Automated tests can run continuously for long durations without fatigue.

Regression Testing: Automated tests are excellent for regression testing, repeatedly checking that existing functionality hasn't been broken by new changes.  

Why not the other options?

B. Usability testing: Focuses on user experience and requires human observation.

C. Ad hoc testing: Informal, unplanned testing without specific test cases.  

D. Manual testing: Performed by humans, which can be time-consuming and prone to errors for repetitive tasks.