Since the 1980s and 1990s, the number of small farms operated by families have _____ as the number of corporate farms have _____.

The correct answer is D. decreased… increased.

Since the 1980s and 1990s, many small family-operated farms have been declining in number due to economic pressures, changes in agricultural practices, and the rise of larger, corporate farms that benefit from economies of scale. This shift has led to an increase in the number of corporate farms. If you have more questions or need further clarification, feel free to ask!