Q. Prior to MySQL 6.0, utf8 was

Explanation by: Praveen Singh

Prior to MySQL 6.0, the utf8 character set in MySQL was capable of storing up to 3 bytes per character. This was an implementation of UTF-8 encoding, but it had a limitation: it could only handle characters that fit within the Basic Multilingual Plane (BMP) of Unicode, which includes most characters, but not all.
In this earlier version of utf8, some characters (like certain emoji or less common scripts) could not be represented because they required more than 3 bytes. This limitation was addressed with the introduction of the utf8mb4 character set, which supports up to 4 bytes per character and allows the full range of Unicode characters.
Therefore, prior to MySQL 6.0, the utf8 character set used 3 bytes per character.