Explanation: Prior to MySQL 6.0, the utf8 character encoding used by MySQL could store characters using up to 3 bytes per character. This allowed for a wide range of characters to be represented, but it had limitations, particularly for characters outside the Basic Multilingual Plane (BMP). MySQL 6.0 introduced utf8mb4 as a new character set that supports up to 4 bytes per character, enabling the storage of the full range of Unicode characters. Therefore, Option A is the correct answer.