Explanation

Creating a filter: as we engage the prompt, we zero in on the pronouns. Pronoun errors, as we have discussed, are common and relatively easy to spot. However, both instances of "it" in this sentence can uniformly and sensibly refer to "use." We can skip (A) and come back to it.

Finding objective defects: the word order is awkward in (B) and the use of "before" imprecise. Moreover, the modifier "especially in children" is misplaced: in the intended meaning, we don't care where and how the demonstrating happens; we care that the bad stuff is absent especially in children. So (B) is out. Choices (C) and (D) and (E) all have a distortion of meaning, because they all are ambiguous as to whether or not the demonstrating has already happened. For example, (D) seems to express that the use doesn't have side effects but won't be recommended. So those three are out. The correct answer is (A).