Consider the following statement According to the Malthusion model
1. Population tends to increase arithmetically.
2. Positive and preventive checks prevent excessive growth rate of population.
3. The basis of preventive checks is moral restraint.
4. Postponement of marriage is to be emplasized.
Of these statements
(a) 1 and 2 are correct
(b) 1, 2 and 3 are correct
(c) 2, 3 and 4 are correct
(d) 1, 3 and 4 are correct