【正确答案】 C

【答案解析】Grammatical construction; Parallelism
The sentence expresses, in an awkward and unclear manner, the thought that the initial development of the motion picture was for science rather than for entertainment. One flaw in the given sentence concerns the placement of not, another flaw is that the pronoun it has no clear antecedent (its antecedent does not seem to be the motion picture, for example).
A The placement of not suggests that it is intended to negate a verbal phrase was first developed, but this makes no sense in context. As noted, the pronoun it lacks a clear antecedent.
B As noted, the pronoun it lacks a clear antecedent. Only if first meant "primarily" could the phrase not first to entertain make some sense in context.
C Correct. This accurately conveys the claim that the intended purpose of the motion picture when it was first developed was not entertainment but something else, i.e., scientific observation. The parallelism between to entertain and to allow removes unnecessary wordiness.
D The placement of not is inappropriate, given the intended meaning. The parallelism noted earlier is missing here.
E The word not seems, misleadingly, to negate the verb first developed, which would fail to convey the intended sense of the given sentence. The antecedent of it is unclear. The parallelism noted earlier is missing here.
The correct answer is C.