a verbal question

The promise of finding long-term technological solutions to the problem of world food shortages seems difficult to fulfill. Many innovations that were once heavily supported and publicized, such as fish-protein concentrate and protein from algae grown on petroleum substrates, have since fallen by the wayside. The proposals themselves were technically feasible, but they proved to be economically unviable and to yield food products culturally unacceptable to their consumers. Recent innovations such as opaque-2 maize, Antarctic krill, and the wheat-rye hybrid triticale (triticale: n.(蛋白质丰富且高产的)小麦与黑麦的杂交麦,黑小麦) seem more promising, but it is too early to predict their ultimate fate.

Which of the following best describes the organization of this paragraph?

(E) A position is stated and evidence qualifying it is provided.

i am puzzled between c and e. what exactly is the difference?