Which of the following fertilisers are covered under the Government of India's Nutrient Based Subsidy scheme?
1. Diammonium Phosphate (DAP)
2. Monoammonium Phosphate (MAP)
3. Triple Super Phosphate (TSP)
4. Single Super Phosphate (SSP) fertilizers
Select the correct answer using the codes given below.
1. 1 and 2 only
2. 1 only
3. 2 and 3 only
4. 1, 2, 3 and 4