Chronologically arrange the following treaties/conventions signed between the Marathas and the British (starting with the earliest) :
1. Treaty of Salbai
2. Treaty of Purandar
3. Convention of Wadgaon
4. Treaty of Surat
Select the correct answer using the code given below :
1. 4 - 2 - 3 - 1
2. 4 - 3 - 2 - 1
3. 1 - 3 - 2 - 4
4. 1 - 2- 3 - 4