View the exhibit and examine the TRANS table‘s storage information. After a massive delete
operation, you executed the following statement to shrink the TRANS table: SQL> ALTER TABLE trans SHRINK SPACE CASCADE;
Which statement describes the outcome of the command? 
A. An error is produced.
B. The table and all related objects are compacted and the position of the high-water mark (HWM) for the table is adjusted
C. The table and related indexes are compacted but the position of the high-water mark (HWM) for the table remains unchanged
D. The unused space in the table is reclaimed and returned to the tablespace and the data manipulation language (DML) triggers on the table are fired during the shrinking process
原文：http://www.cnblogs.com/Babylon/p/7843503.html