Saying that one of them is Linux is too vague. Also, there's nothing to qualify the statements.

If I were to make a comparison, I would say that WordPress is CentOS/RHEL, because it is stable, secure, highly scalable, and can be used for most anything. Drupal would be Ubuntu; it looks pretty and has a lot of built in features (read: bulky), but I wouldn't plan on using it for any legitimate purpose without a lot of work.