Explanation:
Before adding a nonstandard block size to your database you must define a new buffer pool by setting the DB_nK_CACHE_SIZE parameter where n is the new block size. To create tablespaces with multiple block sizes, you must first configure database buffer caches corresponding to the required block sizes. To support this feature, Oracle9i has introduced new initialization parameters. DB_CACHE_SIZE specifies the database buffer cached to the standard block size. Oracle9i can also support four additional block sizes; you can specify the buffer cache size corresponding to each of these block sizes with the db_nK_CACHE_SIZE parameter. It this parameter, nK stands for the nonstandard block size; n can take the following values: 2, 4, 8, 16, or 32.
Incorrect Answers:
2: You cannot redefine the buffer pool by by setting the DB_mK_CACHE_SIZE and DB_nK_CACHE_SIZE parameters, where m is the standard block size and n is the new block size.
3: It’s not possible to rebuild the control file using an instance with an initialization file containing two DB_BLOCK_SIZE parameters.
4: It’s not possible to rebuild the control file using an instance with an initialization file containing two DB_nK_CACHE_SIZE parameters
Reference:
OCP Oracle9i Database: New Features for Administrators, Daniel Benjamin, p. 164-166
Chapter 3: Manageability Enhancements
Oracle 9i New Features, Robert Freeman, p. 14-16
Chapter 1: Oracle9i Database Administration and Management Features

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