the education in china has developed

首先这道题目要填的是副词修饰动词develop，这样a肯定就排除了，改成quickly是可以的。d选项属于逻辑性错误而被排除，只要在b和c里面选一个就可以了。
b和c这两个选项是非常容易混淆的选项。有些形容词有两种副词的形式，一种与形容词同形，一种是由形容词加字尾-ly构成，两者有时区别不大，不带-ly的副词比较口语化。如：
drive slow.
drive slowly.
don't speak so loud.
don't speak so loudly.
he went direct to the office.
he went directly to the office.
在许多情况下两者是有区别的，不带-ly的副词用在直接或具体的场合，带-ly的副词用在比较抽象的场合。如：
jump high
highly developed countries
follow close behind.
she resembles her father closely.
come near
nearly ten o'clock
to produce the sound, you open your mouth wide.
the english language is widely used.
有一些是在意义上完全不同的，如：
pretty good
prettily dressed
work hard
hardly enough
he arrived late for class.
have you seen her lately?
你给出的这题，b表示的是具体的高度，c是抽象的高度，当然在这里是表示抽象的高度，即“中国的教育最近已高度发展”，这个“高度发展”不是你可以用刻度尺量出来的高度，所以选择c。希望我能帮助你解疑释惑。