Electroconvulsive therapy, a longstanding method for treating a variety of psychiatric disorders involving the passing of 800 milliamperes of electricity through the brain, is now administered sparingly, because it engenders considerable controversy due to its association with now outdated and unreliable forms of psychiatric treatment.
Answer: D
Pattern: Subject - Electroconvulsive therapy .., <describe more about therapy, <verb> -> Eliminate B, E for not providing the direct verb
Clarity -> because it engenders or because of engendering? engender is verb and engendering is gerund/present participle to denote the ongoing action of the verb. Eliminate C
For treating or to treat - > both are alright here.
(A) for treating a variety of psychiatric disorders
involving the passing of 800 milliamperes of electricity through the brain, is now administered sparingly, because it engenders - does 'involving' modify psychiatric disorders or does it modify therapy? , because it should modify therapy and modification is not clear here so would eliminate this choice.
(B) for treating a variety of psychiatric disorders, involves the passing of 800 milliamperes of electricity through the brain
and is now administered sparingly because it engenders - No verb before 'and'
(C) for treating a variety of psychiatric disorders involving the passing of 800 milliamperes of electricity through the brain, is now administered sparingly, because
of engendering(D) to treat a variety of psychiatric disorders that involves the passing of 800 milliamperes of electricity through the brain, is now administered sparingly, because it engenders
here 'that' modifies the therapy. D is the best answer .
(E) to treat a variety of psychiatric disorders involving the passing of 800 milliamperes of electricity through the brain,
which is now administered sparingly, engenders - therapy which is now , expect something before which ... also which is usually used for describing optional aspects, however, we need the main verb directly following the therapy.