what are true of Global Secondary Key properties?

When thinking of DynamoDB, what are true of Global Secondary Key properties?

A.
The partition key and sort key can be different from the table.

B.
Only the partition key can be different from the table.

C.
Either the partition key or the sort key can be different from the table, but not both.

D.
Only the sort key can be different from the table.

Explanation:
Global secondary index — an index with a partition key and a sort key that can be different from those on the table. A
global secondary index is considered “global” because queries on the index can span all of the data in a table, across all
partitions.
http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/SecondaryIndexes.html