Thomas Malthus's predictions turned out to be wrong due to:

a. technological advances such as those during the Industrial Revolution.

b. smaller populations now than in the time of Malthus.

c. the effects of brain-drain. unlimited natural resources.

d. None of the above is correct.

The correct answer is letter "A": technological advances such as those during the Industrial Revolution.

Explanation:

British Anglican clergyman and erudite Thomas Malthus (1766-1834) believed the population would grow geometrically, while food production would grow arithmetically. In such a way scarcity will appear in the long run that will require a decrease in the birth rate. However, Malthus's theory has been proven to be wrong so far due to the introduction of technological advances attributed to the Industrial Revolution by the second half of the 18th century which allowed mass-production of goods.