You find pockets of empty space in the USER_DATA tablespace due to a lot of DML operations on the objects in the USER_DATAtablespace. The pockets of empty spaces are too small to be reused individually. This is leading to wastage of space. You decide to perform the shrink operation to reclaim the wasted space. Which advisor will you use to determine the objects in the USER_DATA tablespace that are good candidates for the shrink operation？（）

A. SQL Tuning Advisor
B. SQL Access Advisor
C. Undo Advisor
D. Segment Advisor