Which of the following sentences from the introduction (paragraphs 1-2] BEST develops a central idea of the article? (A)
Agricultural methods have intensified continuously ever since the Industrial Revolution, and even more so since the green revolution in the middle decades of the 20th century.

(B)
This tremendous rise in food production has sustained a global population that has quadrupled in size
over the span of one century.

(C)
In the coming decades, however, meeting the demand for accelerated agricultural productivity is likely to
be far more difficult than it has been so far.

(D)
Many of the techniques and modifications on which farmers rely to boost output also bring harmful environmental effects.