Which of the following is TRUE with regards to columnstore indexes?

You work as a developer at ABC.com. The ABC.com network consists of a single domain named
ABC.com.
ABC.com has a SQL Server 2012 database table that includes a million rows. You have
configured a column in the table with a columnstore index.

Which of the following is TRUE with regards to columnstore indexes?

A.
It is an index structure separate from the data stored in a table that reorders one or more
selected columns.

B.
It guarantees that the index key contains no duplicate values and therefore every row in the
table is in some way unique.

C.
A table with a columnstore index cannot be updated.

D.
It is an optimized nonclustered index especially suited to cover queries that select from a welldefined subset of data

Explanation: