Numbers prefixed with '0x' are in base . . . . . . . .

This question is about how MySQL represents numbers.

In computer science, we use different number systems to represent values. The most common ones are:

* Decimal (base 10): This is the system we use every day, with digits from 0 to 9.
* Binary (base 2): This system uses only 0s and 1s. Computers use binary to store information.
* Octal (base 8): Uses digits from 0 to 7.
* Hexadecimal (base 16): Uses digits 0-9 and letters A-F to represent values.

MySQL uses the '0x' prefix to indicate that a number is in hexadecimal (base 16). This makes it easier to represent large binary values in a more compact way.

So the correct answer is Option B: 16.