Explanation:
The LOG_BUFFER parameter value must be a multiple of the database block size, DB_BLOCK_SIZE parameter.
Incorrect Answers:

1: The LOG_BUFFER parameter cannot be changed dynamically. You can edit this parameter, but it will be changed only after instance restart.
2: The minimum value for the LOG_BUFFER parameter is not 512 KB, it can be less.
4: The LOG_BUFFER parameter value must be a multiple of the database block size, not operating system block size.

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