The question does not provide any specific criteria or category which needs to be followed to arrange these countries. However, the correct answer is option 3, which orders the countries as Sri Lanka, India, Pakistan, and Bangladesh. Here`s a possible rationale behind such arrangement:

1. Sri Lanka (4) - It`s the southernmost country in South Asia.

2. India (2) - Situated north to Sri Lanka and central to the South Asian region.

3. Pakistan (3) - In the west of India.

4. Bangladesh (1) - Lies to the east of India.

Without more context or specific parameters (like arranging them as per their sizes or populations etc.), it`s difficult to explain the logic behind this order correctly.