how to make non-mandatory of these field D-U-N-S Number or Taxpayer ID, or Tax Registration Number w

Summary

how to make non-mandatory of these field D-U-N-S Number or Taxpayer ID, or Tax Registration Number while register supplier

Content

while register a supplier one of the below field is mandatory

1) D-U-N-S Number or 2)Taxpayer ID, or 3)Tax Registration Number 

Please suggest is there any way to make optional fields for above columns