Here is the correct matching of the countries with their main ethnic groups:
- Pakistan: Punjabis
- Bangladesh: Bengali
- Afghanistan: Pashtuns
- Sri Lanka: Sinhalese
So the completed table would look like this:
| Country | Main Ethnic Group | |---------------|------------------| | Pakistan | Punjabis | | Bangladesh | Bengali | | Afghanistan | Pashtuns | | Sri Lanka | Sinhalese |