Hi
Skywalker18,
I'm not sure that I understand your question.
AjiteshArun is totally correct in saying that our situation here is a relative clause. When a relative clause refers to the OBJECT of the previous clause, "that" is optional.
Example 1:
I can't find the shoes that I like. -> relative clause is "that I like." "I" is the subject of the relative clause, and the shoes (represented also by "that") are the object. So we could also correctly write:
I can't find the shoes I like.Example 2:
I can't find the shoes that are comfortable.-> relative clause is "that are comfortable." Here, the shoes are the SUBJECT of the relative clause. So, I
cannot leave out "that".
(See for yourself:
I can't find the shoes are comfortable??? What?? It's not understandable.)
I can't think of a situation where "that" could join two independent clauses, since "that" would typically make the second clause dependent. But let me know if you have an example.
***
sonusaini1You asked whether answer C could be a good option if we removed the redundancy.
Well, it would be better than it currently is. But compare it again to our winning answer E.
What's different?
C is wordier because it is
passive (sales that in the past would have been conceded to rivals). Meanwhile, E is active (sales it would in the past have conceded to rivals.)
When everything else is equal, prefer the active to the passive. Usually, it makes the sentence shorter and more direct.
***
Best, Jenn