急求解答，谢谢～～

Responding to the public’s fascination with-and sometimes
        undue alarm over-possible threats from asteroids, a scale
            developed by astronomers rates the likelihood that a particular asteroid or comet may collide with Earth.

A.    a scale developed by astronomers rates the likelihood
        that a particular asteroid or comet may

B.     a scale that astronomers have developed rates how
        likely it is for a particular asteroid or comet to

C.    astronomers have developed a scale to rate how likely
            a particular asteroid or comet will be to

D.    astronomers have developed a scale for rating the
        likelihood that a particular asteroid or comet will

E.     astronomers have developed a scale that rates the
        likelihood of a particular asteroid or comet that may

为什么是C不是E

E后面that有问题

C表示目的用to do ， how likely ...will be.表示发生概率的大小

我觉得likelihood 和 may redundant~

而且likely 明显优于likelihood～形容词优于抽象名词

agree

而且E中有likelihood了后面又出现may 感觉有点重复，C中do sth to do sth 感觉很顺