Final answer:
option c.B-trees are the correct choice of data structure for secondary storage in databases and filesystems due to their efficiency in handling large blocks of data and reducing disk accesses.
Step-by-step explanation:
The correct data structure for secondary storage that is commonly used in databases and filesystems is c) B-trees. B-trees are a type of self-balancing tree data structure that maintains sorted data and allows searches, sequential access, insertions, and deletions in logarithmic time.
They are extremely useful in systems that read and write large blocks of data, such as databases and file systems. B-trees are optimized for systems that read and write large blocks of data, which is a common characteristic of secondary storage devices.
They are chosen over other data structures like binary trees, linked lists, and heaps because they reduce the number of disk accesses required when managing large datasets. Therefore, B-trees offer an efficient way to index large volumes of data in a way that minimizes read/write times, improving the overall performance of the database or file system.