Using the most reliable information available, how much of the earth's land surface is used for agriculture today?

a) 10%, according to government surveys of land use
b) 30 to 40%, according to satellite imagery
c) 70%, according to surveys conducted by commercial jets
d) 90%, according to tax records from government agencies

b)

Explanation:

"As of the year 2000, about 37 percent of Earth's land area was agricultural land."

https://www.learner.org/courses/envsci/unit/text.php?unit=7&secNum=2

d. stage 4

explanation:

the existence of some kind of demographic transition is widely accepted in the social sciences because of the well-established historical correlation linking dropping fertility to social and economic development.[1] scholars debate whether industrialization and higher incomes lead to lower population, or whether lower populations lead to industrialization and higher incomes. scholars also debate to what extent various proposed and sometimes inter-related factors such as higher per capita income,lower mortality, old-age security, and rise of demand for human capital are involved.[2]