If a string is to be converted to a number, it is converted into a . . . . . . . .

This question is about how MySQL handles strings when you try to turn them into numbers.

Let's break down the options:

Option A: double precision floating point - This is a type of number that can have decimals and a very large range, like really big or really small numbers.
Option B: single precision floating point - Similar to a double precision, but has a smaller range of numbers.
Option C: decimal integer - This is a whole number, no fractions or decimals.
Option D: hexadecimal integer - This is a number system using base 16, often written with letters and numbers.

When MySQL turns a string into a number, it usually tries to make it a double precision floating point number. This means it can handle decimals and a wide range of numbers.

So the correct answer is Option A: double precision floating point.