Section: Deductions
Class C contains a minimum of 2 children and a maximum of 3 children who have a classmate who has a birthday on the same day and all children who have a birthday on the same day have blonde hair. Lisa's birthday is December 2, but there is no mention of her hair color. Karin is blonde, but it is not known when it is her birthday. Peter and Kyra have their birthday on the same day.
Conclusion
Lisa and Karin do not have their birthday on the same day.