Sentence Correction

It has been said that all one can do for a sprained ankle is leave it alone while it heals itself, ice it, and to lie with it in a slightly elevated position

(A) all one can do for a sprained ankle is leave it alone while it heals itself, ice it, and to
(B) all one can do for a sprained ankle is to leave it alone to heal itself, to ice it, and
(C) all one can do for a sprained ankle is leave it alone while it heals itself, and then ice it and
(D) the only thing that can be done for a sprained ankle is leave it alone while it heals itself, ice it, and
(E) the only thing that can be done for a sprained ankle is to leave it alone while it heals itself, to ice it, and
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It is an oversimplified view of cattle raising to say that all one has to do with cattle is leave them alone while they feed themselves, corral them, and to drive them to market when the time is ripe.

(A) all one has to do with cattle is leave them alone while they feed themselves, corral them, and to
(B) all one has to do with cattle is to leave them alone to feed themselves, to corral them, and
(C) all one has to do with cattle is leave them alone while they feed themselves and then corral them and
(D) the only thing that has to be done with cattle is leave them alone while they feed themselves, corral them, and
(E) the only thing that has to be done with cattle is to leave them alone while they feed themselves, to corral them, and

As per the official answers, its D and C.

I have checked a many forums to understand the reason for different OA. Both the sentence construction are same .. so what should be final answer and why??

Does it have anything to do with the missing comma in the second C?