Robin Corporation is owned as follows: 

Isabelle.................................................26% 

Peter, Isabelle’s husband...................19% 

Sonya, Isabelle’s mother....................15% 

Reggie, Isabelle’s father......................25% 

Quinn, an unrelated party.................15% 

Robin is on the accrual basis, and Isabelle and Peter are on the cash basis. Isabelle and Peter each loaned Robin Corporation $40,000 out of their separate funds. On December 31, 2019, Robin accrued interest at 7% on both loans. The interest was paid on February 4, 2020. What is the tax treatment of this interest expense/income to Isabelle, Peter, and Robin?