My 8 y/o passed out birthday invitations to everyone instead of just the boys in his class

I need help on how to handle this situation. My son's school has a rule that if you pass out invitations at school you must either invite everyone or all of the kids of the same sex. We opted to invite all the boys. This was discussed with my son several times and we have only invited the boys in his class to his parties. Somehow, he forgot and passed the invitations out to everyone. The party venue I booked has a max capacity of 50 people. If everyone invited rsvps we will be over capacity and I didn't order enough food or cake to accommodate 20 extra kids/parents.

My ideas so far: A) Reach out to the teacher explain the mistake and get contact info to reach out to the girls parents to explain and apologize.

B) Have my son give the girls apology notes with a little gift bag of treats.

How do I fix this?

Update: Ya'll are awesome! Thanks to everyone for your input. After reading the comments, I agree it would be tactless to uninvite the girls.