小华同学为了研究“弦乐器的音调跟哪些因素有关”，他自制了一把“吉他”，通过研究发现，弦乐器音调与下列因素无关的是 [ ]

A．弦的长度

B．弦的粗细

C．弦的松紧程度

D．用力大小

_____ want to devote their whole life to their career should go _____ there are various career opportunities.

A．Whoever; where

B．Those who; where

C．Whoever; in which

D．Those who; in which