PHP variables are preceded by . . . . . . . .

This question is asking about how you identify variables in the PHP programming language.
Variables are like containers that hold data in your program.
Think of it like a box where you can put different things inside.

To tell PHP which box you are talking about, you need to use a special symbol in front of the variable name.

Out of the given options, the correct symbol for PHP variables is: $
So the answer is Option C.

For example, if you want to store the number 10 in a variable named "my_number", you would write: $my_number = 10;
The $ tells PHP that "my_number" is a variable, not just a word.