What is the result of using a variable name that starts with a number?

Using a variable name that starts with a number is illegal in most programming languages, including JavaScript, Python, and others. Variable names must begin with a letter (either uppercase or lowercase) or an underscore. This rule is in place to maintain clarity and consistency in the code, as variable names are often used to represent data and functionality.

If a variable name were allowed to start with a number, it could create confusion in parsing expressions and could lead to syntax errors. This restriction helps prevent potential conflicts with numerical literals and ensures that the variable naming conventions are straightforward and easy to read.

Other choices hinge on misconceptions regarding variable naming conventions. While underscores can be part of a variable name, they cannot allow a name to legally start with a number.