Php / Basics / Constants - https://www.minte9.com/php/basics-constants-23

index.php

<?php

/**
 * Define getMaxValue() method
 * Use static syntax
 */
class MyClass {

    const MAX_VALUE = 100;

    /**
     * SOLUTION
     */
    public static function getMaxValue() {

        return self::MAX_VALUE;
    }
}

echo MyClass::getMaxValue(); // 100