Which of the following best describes the processing model for how the MySQL server handles queries?

A. The server uses a one-tier processing model in which each storage engine optimizes and processes each query issued against it.  
B. The server uses a two-tier processing model: a SQL/optimizer tier and a storage engine tier.
C. The server uses a three-tier processing model: a SQL/optimizer tier, a formatting tier and a storage engine tier.

Answer: B