Which I/O scheduling algorithm is designed to reduce the average response time for disk operations by prioritizing requests based on proximity to the current head position? 

The Shortest Seek Time First (SSTF) I/O scheduling algorithm is designed to optimize the order in which disk I/O requests are serviced by selecting the request that is closest to the current head position of the disk arm. This approach minimizes the seek time— the time it takes for the disk's read/write head to move to the location of the data to be read or written— thereby reducing the average response time for disk operations. SSTF improves overall system efficiency by ensuring that the most immediate requests are handled first, decreasing waiting times for processes that rely on disk access. However, while SSTF enhances average response time, it may lead to starvation for requests located further from the current head position, as these requests may continually be deferred in favor of closer ones. Therefore, while SSTF strikes a balance between efficiency and responsiveness, it is essential to be mindful of its potential impact on fairness in resource allocation. Option A (FCFS) - First-Come, First-Served is a straightforward scheduling method that can lead to increased wait times, especially if a lengthy seek operation occurs before shorter requests. Option C (SCAN) - The SCAN algorithm moves the disk arm in one direction, servicing requests until it reaches the end before reversing. While effective, it does not prioritize requests based on proximity. Option D (LOOK) - LOOK is similar to SCAN but only goes as far as the last request in one direction before reversing, which may still leave some requests unserviced for a long time. Option E (Round Robin) - Round Robin is typically used for CPU scheduling rather than I/O scheduling, where requests are serviced in a cyclical order without considering their location.