Which of the following is NOT a valid variable name in PHP?$_variable$1_variable$variable$my_variableClear my choice

To determine which option is NOT a valid variable name in PHP, we can evaluate each choice based on PHP's variable naming rules. In PHP, variable names must start with a letter or an underscore, followed by any number of letters, numbers, or underscores. Dollar signs are used for declaring variables but cannot be included in the variable name itself.

1. $_variable: This is valid because it starts with an underscore.

2. $1_variable: This is NOT valid because it starts with a digit.

3. $variable: This is valid because it starts with a letter.

4. $my_variable: This is valid because it starts with a letter.

Final Answer

The option that is NOT a valid variable name in PHP is $1_variable.