With reference to the Malthusian theory of population growth, consider the following statements:

1. Any rise or fall in the optimum level of population of a region will diminish the income per head of the population.

2. The number of people would increase faster than the food supply leading to a population crash.

3. The population growth rate of the world is directly proportional to the levels of literacy.

Which of the statements given above is/are correct?