415协议的 15号怎么看?

mathszUID: 2218668

Students are under no obligation to respond to offers of financial support prior to April 15; earlier deadlines for acceptance of
such offers violate the intent of this Resolution. In those instances in which a student accepts an offer before April 15, and subsequently
desires to withdraw that acceptance, the student may submit in writing a resignation of the appointment at any time
through April 15.


第一句话的prior to April 15怎么解释？包括415吗？是不是一定要在学校所在时间的4月14号晚上11点59分之前答复，到了12点，那边的人就有权利把offer转给别人？ 还是到了15号晚上的11点59分才……

最后那句话的through是什么意思？

jorgeUID: 108878

Including April 15th