You manage a SQL Server 2005 database that contains a table with many indexes. You notice that data modification performance has degraded over time. You suspect that some of the indexes are unused. You need to identify which indexes were not used by any queries since the last time SQL Server 2005 started. Which dynamic management view should you use？（）

A. sys.dm fts index population
B. sys.dm exec query stats
C. sys. dm db index usage stats
D. sys.dm db index physical stat