It is an oversimplified view of cattle raising to say that all one has to do with cattle is
leave them alone while they food 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

OA IS C