I'll say C.
Because of the colon, you can eliminated choices D and E. The colon plays a role similar to if the word "namely" were used instead of the colon in the sentence. Therefore would you say, "...the ultimate goal in ultimate husbandry, namely achievement of..." No. So D and E are out.
Consider A, B and C.
What role is "as" playing in "in farm animals as once thought to be...". It seems out of place, do you agree? Scratch A.
Can you "achieve farm animals..." - no! That doesn't make sense. Scratch B.