The diagram illustrates the arrangement of a simple transformer. Which row indicates the conditions needed for the transformer’s efficiency to be as high as possible?
- Aprimary and secondary coils: thick copper wire; core: soft iron
- Bprimary and secondary coils: thin copper wire; core: soft iron
- Cprimary and secondary coils: thick iron wire; core: copper
- Dprimary and secondary coils: thin iron wire; core: copper