Answer: The option that revises the sentence to create a new, complex sentence is the third one: Based on the scientists’ recommendations, the new safety requirements were enacted so that the number of accidents diminished.
Explanation: A complex sentence is a sentence made up of an independent clauses and a dependent clause. However, unlike an independent clause, a dependent clause cannot stand alone as a sentence because it does not present a complete thought. Moreover, a dependent clause is introduced by a subordinating conjunction. The sentence "Based on the scientists’ recommendations, the new safety requirements were enacted so that the number of accidents diminished" revises the sentence provided, which was only made up of an independent clause, by including a dependent clause and transforming it into a complex sentence. The dependent clause in the new sentence is "so that the number of accidents diminished" and the subordinating conjunction that introduces it is "so that".
