Most Year 3 students in Quzhou No.1 High School are working hard day and night for the 2014 college entrance examinations, hoping to gain __________ to their dream universities.

A．application

B．admission

C．connection

D．agreement

已知氮肥尿素的化学式为[CO（NH₂）₂]，试计算下列各题．

（1）计算尿素中C、O、N、H各元素的质量比．

（2）若某块庄稼地中的作物经“庄稼医生”诊断需140kg的氮元素，则需尿素的质量是多少？