Wtf past perfect needed if there is clear reference that one

Question

Wtf past perfect needed if there is clear reference that one thing happened after another???
here is rule:
If the Past Perfect action did occur at a specific time, the Simple Past can be used instead of the Past Perfect when "before" or "after" is used in the sentence. The words "before" and "after" actually tell you what happens first, so the Past Perfect is optional. For this reason, both sentences below are correct.

Examples:
She had visited her Japanese relatives once in 1993 before she moved in with them in 1996.
She visited her Japanese relatives once in 1993 before she moved in with them in 1996.
https://www.englishpage.com/verbpage/pastperfect.html

kostyan5 · Answer

To me, the only other viable option is E. The use of 'which' is wrong here, and D is incorrect.

liftoff · Answer

I believe the answer is E. The use of that or which would be redundant.

imaggic · Answer

I am also more inclined towards E.

rustypolymath · Answer

I don't think that rule is applicable here, since the second clause here is a relative clause and not a subordinate clause. Not merely subordinate to the main clause, it is on an altogether lower semantic level and therefore doesn't have the same "liberty" for its syntaxes.

jeprince112 · Answer

i would choose C as well... so is that not the official answer? I figure "had" needs to be used.

Wtf past perfect needed if there is clear reference that one

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