A teacher at the Our Redeemer Lutheran School, has sparked outrage after asking students to come up with three good reasons why it was good for people to own slaves.

Local news station Fox 6 Now reports that a teacher at a Lutheran school in Wauwatosa, Wisconsin gave students a homework assignment that asked them to list the potential positives and potential negatives of slavery.

A black mom, whose son was one of the students asked to complete the assignment, told Fox 6 Now that she was appalled that any teacher would ask her kid to think of good reasons for his ancestors to be enslaved by white people.

“It’s highly offensive and insensitive,” Parent Trameka Brown-Berry explains to the news station. “I was in shock. I couldn’t believe they sent something like that home. Not only was my son in an awful position, but the students who weren’t black — that’s what keeps racism going.”

Jim Van Dellen, the principal at Our Redeemer Lutheran School issued a formal apology while adding that students shouldn’t have bothered to complete the assignment because there are no good reasons for slavery.

“The purpose of the assignment was not, in any way, to have students argue that slavery is acceptable,” he wrote in a letter to parents.