I was checking out the minimum admission requirements of UCs, and it says that no more than 14 semester (21 quarter) units may be taken Pass/Not Pass. Does it mean before I apply or the end of the spring term? And do those units that I get from ap exams count in these 21 units? Also it says that I need to finish two transferable courses in English composition/critical thinking and writing. Can those two course be Pass/Not Pass or they have to be letter grade?