Answer:
c. $10th
Explanation:
In order to declare or create a valid variable in PHP, there are rules and guidelines to follow, these the following:
1. Valid variable begins with the $ sign.
2. It must begin with a letter or the underscore character only.
3. Valid variable cannot begin with a number after the $ dollar sign.
4. It can only contain alpha-numeric characters and underscores
5. Valid variable name is case-sensitive
Hence, given these rules and guidelines, the correct answer is option C, which after starting with $ sign begins with a number character.
