wotc
For each player, choosing a target creature that player controls is optional.
For each player, choosing a target creature that player controls is optional.
All counters on a creature are considered when determining the value of X, not only +1/+1 counters.
Your opponents can choose not to pay to attack with a creature with one or more counters on it that attacks "if able." If there's no other player or planeswalker to attack, the creature simply doesn't attack.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Magali Villeneuve
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.