7.Daniel and Patrick had an equal number of stickers at first. Daniel then gave away 20 of his stickers to his friend Melvin, and Patrick bought another 12 stickers. In the end, Patrick had thrice as many stickers as Daniel. Find the number of stickers Daniel had at first? 
选项为:A:$$35$$  B:$$36$$  C:$$37$$  D:$$38$$  请回答其中一个选项.