The correct answer is option 4: 1, 2 and 3.

1. The first statement is correct. Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) was launched during the year 2015-16.

2. The second statement is correct. The basic aim of PMKSY is to enhance physical access to water on the farm. This means providing irrigation facilities to farmers to ensure enhanced water availability for agricultural purposes.

3. The third statement is also correct. One of the main objectives of PMKSY is to achieve convergence of investments in irrigation at the field level. This means bringing together different stakeholders and investments to ensure effective and efficient utilization of resources in irrigation projects.

Therefore, all three statements are correct, and the correct answer is option 4: 1, 2 and 3.