Final answer:
An SSTable on BigTable is a type of database table used for efficient data retrieval and storage.
Step-by-step explanation:
An SSTable on BigTable refers to a type of database table. SSTable stands for Sorted String Table, which is a file format used by BigTable to store data in a sorted order. Each SSTable file contains key-value pairs, where the keys are sorted in a specific order, allowing for efficient data retrieval and searching.
For example, in BigTable, if you have a table called 'users' and you want to retrieve information about a specific user, the SSTable provides a way to quickly locate and retrieve the data corresponding to that user.
So, the correct option is a) A type of database table.