Would you like to ____my birthday party?A join in B join C take part in D take part.

1) join及物动词加入（团体,组织,参军）、同……一起干或玩、连接
例句：①I joined the Party in 1975.（我1975年入党.）
2) join in 参加（某些活动）
例句：①May I join in your discussion?（我可以参加你们的讨论吗?）
3) take part in 参加（群众性活动,会议等）参加者持积极态度,起一份作用.
例：①A lot of students took part in the thorough cleaning yesterday.昨天许多学生参加大扫除.
4）take part 参加,参与
People who take part in sports must be in condition.
参加运动的人一定能保持良好的健康状态.
所以应该选C