The fourth alternative is correct (D).
Thomas Mautus had a pessimistic theory in which the population of the land would grow faster than the productivity of the land, which provides food. According to Mautus, the population would grow in geometric progression, while the productivity of the soil would grow in aritimética progression.
In this way, Mautus believed that population control would be made by lack of food. In this context, a society with fewer children would have more food available to meet the needs of the population.