Which of the following is an example of a good Amazon DynamoDB hash key schema for provisioned throughput efficiency?

Answer options:

A.Student ID where every student has a unique ID.B.College ID where there are two colleges in the university.
C.Class ID where every student is in one of the four classes.
D.Tuition Plan where the vast majority of students are in state and the rest are out of state.

Answer – A
Option A is CORRECT because DynamoDB stores and retrieves each item based on the primary key (hash key) value which must be unique. Every student would surely have a Student ID. Hence, the data would be partitioned for each ID, which will make the data retrieval efficient.
Option B is incorrect because the data should spread evenly across all partitions for the best throughput. With only two colleges, there would be only two partitions. This will not be as efficient as making Student ID the hash key. 
Option C is incorrect because partitioning on the Class ID will not be as efficient as doing so on the Student ID.Option D is incorrect because there are only two possible options: in-state and out-of-state. This will not be as efficient as making Student ID the hash key.
For more information on DynamoDB tables, please visit the URL:
http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html