(A) This is unique to Harris's argument, eliminate.
(B) We don't know if hybrids are considered engendered, only that harris thinks they should be protected.
(C) This is unique to Vogel's argument as it is provided to substantiate his claim that hybrids need not be protected.
(D) Bingo. Harris thinks that they should be because they are not currently protected and because they are descendants of independent species who presumably are protected. Vogel disagrees because in the event that they become endangered they can be revived through more interbreeding.
(E) No, this is discussed briefly by Harris as a technique to ascertain whether or not hybrids are the product of interbreeding, techniques in genetic research were not even discussed by Vogel.
It helps to create a visual map in your head of the dialogue (although during the test this must be an internal process as you won't have the time to draw this out). The correct answer will be the point of overlap between the two and not those which are unique to one of the agent's argument. This is because they can only disagree about something on which they both have an opinion.
Hybrid species currently protected by international endangered species regulations:
Harris: No
Vogel: N/A
Hybrids should be protected:
Harris: Yes (because they are not protected by international endangered species regulations and other species are)
Vogel: No (if they die out, the independent species from which they descend can just bang and revive the species)
Revival of engendered species:
Harris: N/A
Vogel: Interbreeding of independent species.