The earliest site where human civilization and crop cultivation started was presumably

There was nothing natural or inevitable about the development of agriculture. Because cultivation of plants requires more labor than hunting and gathering, It was assumed that during the stone age, humans gave up their former ways of life reluctantly and slowly. But between about 8000 and 3500 B.C., increasing numbers of humans shifted to dependence on cultivated crops and domesticated animals for their subsistence. Over time, their tools and skills had advanced sufficiently for cultivating peoples to support towns with over one thousand people. By 3500 B.C., agricultural peoples in the Middle East could support sufficient numbers of non-cultivating specialists to give rise to the first civilizations.

Thus, the correct answer is option A.