Final answer:
The point of crisis in Malthus' Theory, known as the Malthusian trap, occurs when exponential population growth surpasses linear increases in food production, leading to famine and other 'positive checks' that reduce the population.
Step-by-step explanation:
In Thomas Malthus' Basic Theory, the point of crisis, or the Malthusian trap, is defined as (b) The point at which population growth exceeds food production. The crisis emerges when the food required by the population, which grows exponentially, outpaces the food produced, which according to Malthus, can only increase linearly.
This results in a situation where the available food supply is insufficient to support the growing population leading to starvation, disease and potentially war as these 'positive checks' work to reduce the population down to a sustainable level.