x'ffff' in decimal is . . . . . . . .

Answer: Option C

This question is about how MySQL represents numbers in different formats.

Let's break it down:
* 'ffff': This is a hexadecimal number. Hexadecimal uses 16 digits (0-9 and A-F) to represent numbers. 'f' in hexadecimal is equivalent to 15 in decimal.
* x'ffff': The 'x' prefix tells MySQL that the following characters are a hexadecimal value.
* Decimal: This refers to the standard base-10 system we use for everyday numbers.

To convert 'ffff' from hexadecimal to decimal, we need to understand place values:
* f (rightmost) represents 15 * 16^0 = 15
* f (second from right) represents 15 * 16^1 = 240

Adding these values: 15 + 240 = 255

Therefore, x'ffff' in decimal is 65535.

The correct answer is Option B: 65535