Which statement about indexes is true? | Teradata

A.both primary and secondary indexes can be created any time during the life time of a table.
B. Both primary and secondrey indexes  must be specified during table creation.
C.A secondrey index is created when a table is created , and a primary index is created any time during the life time of a table.
D. A primary index is created  when a table is created, A secondrey index is created any time during the life time of a table.

Ans: D