<p dir="ltr" style="text-align: justify;"><span><span style="">A verb after a preposition should take the form of V-ing as a gerund to be the object of the preposition instead of the basic form (Choice (B)</span><span style=""> prevent</span><span style="">) or the form of to-infinitive (Choice (C) </span><span style="">to prevent</span><span style="">). Thus, the correct answer is (A) </span><span style="">preventing</span><span style="">. </span></span></p><p><br></p><p dir="ltr" style="text-align: justify;"><span><span style="">It is true that a noun can follow a preposition too, but here (D) </span><span style="">prevention</span><span style=""> is incorrect because it cannot directly connect with the following words “non-smoking workers from breathing in secondhand smoke.” </span></span></p>