What are some common pitfalls to avoid when processing PHP form submissions with predefined answers?

One common pitfall to avoid when processing PHP form submissions with predefined answers is not properly validating the user input against the predefined options. To solve this issue, you should always check if the submitted value matches one of the predefined answers before processing the form.

// Define predefined answers
$predefined_answers = array("option1", "option2", "option3");

// Check if the submitted value is in the predefined answers
if (in_array($_POST['answer'], $predefined_answers)) {
    // Process the form submission
    // Your code here
} else {
    // Handle invalid input
    echo "Invalid answer submitted";
}