Bunuel
Once the physiological effects and anesthetic qualities of diethyl ether were demonstrated
and with its superiority to chloroform being proved by William Morton, the medical community rapidly adopted it as the anesthetic of choice.
(A) and with its superiority to chloroform being
(B) and its superiority to chloroform
(C) and its superiority over chloroform had been
(D) its superiority over chloroform
(E) with its superiority to chloroform having been
(A) and with its superiority to chloroform being (with its superiority to chloroform being proved by William Morton is a correct prepositional phrase which is modifying 'the medical community rapidly adopted it as the anesthetic of choice'. Also two independent clauses are correctly joined with and.)
(B) and its superiority to chloroform (excluding with makes the sentence looks like the superiority of diethyl ether doesn't exist before being proven by William Morton)
(C) and its superiority over chloroform had been (The usage of had been makes clause after and an independent clause. And also the last clause is also independent so they can't be joined together with a comma)
(D) its superiority over chloroform (exclusion of and makes the two independent clauses joined by a comma. Incorrect)
(E) with its superiority to chloroform having been (having been proved makes the clause looks like the superiority is still in process of being proven. Thus incorrect)