Peter invested his savings of $875 in a savings account that was earning a simple interest rate of 2.55% p.a. He also invested $3,925 in his friend's business at a simple interest rate of 0.28% p.m. a. What is the simple interest rate per month that is equivalent to 2.55% p.a.? 0.04% 2.13% 0.02% 0.21%