Purebred cows native to Mongolia produce, on average, 400 liters of milk per year, if Mongolian cattle are crossbred with European breeds, the crossbred cows can produce, on average, 2,700 liters per year. An international agency plans to increase the profitability of Mongolia’s dairy sector by encouraging widespread crossbreeding of native Mongolian cattle with European breeds.
Which of the following, if true, casts the most serious doubt on the viability of the agency’s plan
A．Not all European breeds of cattle can be successfully bred with native Mongolian cattle.
B．Many young Mongolians now regard cattle raising as a low-status occupation because it is less lucrative than other endeavors open to them.
C．Mongolia’s terrain is suitable for grazing native herds but not for growing the fodder needed to keep crossbred animals healthy.
D．Cowhide and leather products, not milk, make up the bulk of Mongolia’s animal product exports to Europe.
E．(E) Many European breeds of cattle attain average milk production levels exceeding 2,700 liters.
