Thomas Malthus Believed That There Were Preventives Checks and Positive

Thomas Malthus believed that there were preventives checks and positive checks on population growth. What are these preventive and positive checks?

A) preventive checks include restraint and birth control; positive checks include famine and war.
B) positive checks include restraint and birth control; preventive checks include famine and war.
C) positive checks include an expanding food supply; preventive checks include poverty.
D) positive checks include bribes and other monetary rewards; preventive checks include taxes and fines.