The default scheduling property of MySQL is implemented by how many of these? MyISAM, MERGE, MEMORY

Answer: Option D

This question is about how MySQL handles scheduling tasks, like when to run certain queries.

The question asks: How many of these storage engines use the default scheduling property?

Let's look at each option:
* MyISAM is a storage engine, but it doesn't handle scheduling tasks.
* MERGE is a storage engine, but it doesn't handle scheduling tasks.
* MEMORY is a storage engine, but it doesn't handle scheduling tasks.

Since none of the options are involved in scheduling, the answer is Option A: 0.