The passage mentions all of the following as factors important to the success of a new food crop EXCEPT the ______.

A．a suggestion is made and arguments in its favor are provided.
B．a criticism is imposed and an alternative proposal is suggested.
C．a generalization is advanced and supporting evidence is provided.
D．an example is analyzed and general conclusions are derived from it.

A．means of assessing the extent of the world food shortage
B．difficulties of applying technological solutions to the problem of food shortage
C．costs of introducing a new food technology into a developing country
D．nature of the new technological innovations in the area of food production