Tax relief at source is available on which of the following? 1) Mortgage interest on a principal private residence located in Ireland 2) Mortgage interest on a principal private residence located in Northern Ireland 3) Permanent Health Benefit Schemes 4) Health Insurance Schemes (e.g., VHI) O a. 1 and 4 O b. 1, 2 and 3 O c. 2 and 4 Od. 2,3 and 4