Hey All,
A lot of conversation here, but no one has yet really gone through it piece by piece and explained what the heck is going on. I'll be that guy!
The verb "to require" can function in two ways. The first is passive: "Something is required TO do something". In this format, we have the passive voice of required. You can't go active (It's not allowed to say "He requires you to do something."), and you have to use the infinitive form of the subordinate verb. THE OTHER version of the verb "to require" is active, and forms the subjunctive of demand (We call them bossy verbs). Bossy verbs always form the same way:
BOSSY VERB CONSTRUCTION: HE demanded THAT Sheila dance.
subject normal verb always have "that" Object verb in the subjunctive
The verb in the subjunctive may be tough to recognize. However, the typical present tense form that goes with the subject "Sheila" is "dances". The subjunctive is generally formed by taking the infinitive form of the verb ("to dance") and removing the "to".
Okay. Now let's look at the question.
3. Legislation in the Canadian province of Ontario requires of both public and private employers that pay be the same for jobs historically held by women as for jobs requiring comparable skill that are usually held by men.
(A) that pay be the same for jobs historically held by women as for jobs requiring comparable skill that are
ANSWER: Here we have "requires" in the active voice, so we need the bossy verb construction. We get the THAT we need, then the object "pay", then the subjunctive form "be" (it's the infinitive "to be" without the "to"). Looks good!
(B) that pay for jobs historically held by women should be the same as for a job requiring comparable skills
PROBLEM: YOU NEVER USE SHOULD in a subjunctive construction. In fact, should gets used SO OFTEN in these types of questions, that it's worth noticing it in all the sentences you look at. Often, it signals a bossy verb subjunctive construction that you might not have noticed otherwise!
(C) to pay the same in jobs historically held by women as in jobs of comparable skill that are
PROBLEM: The "to" is wrong for the subjunctive construction. Also "in jobs" is an incorrect idiom. It should be "for jobs".
(D) to pay the same regardless of whether a job was historically held by women or is one demanding comparable skills
PROBLEM: The "to" is wrong for the subjunctive construction. Also the parallelism is wrong. The wrong two things are being compared.
(E) to pay as much for jobs historically held by women as for a job demanding comparable skills
PROBLEM: The "to" is wrong for the subjunctive construction. "Jobs" and "a job" aren't parallel.
Hope that helps!
-t