Northern and southern states compromised on the slave trade by
agreeing to continue the slave trade indefinitely
agreeing not to end the slave trade for at least 20 years
agreeing to end the slave trade immediately
agreeing to continue the slave trade for a maximum of 50 years

The correct answer is agreeing not to end the slave trade for at least 20 years.

In order to compromise on the issue, individuals from the north and south had to find a middle ground in terms of the slave trade. This is why the slave trade would be banned as of 1808. When they made this agreement in 1788, this satisfied both parties as the northerners wanted to stop this inhumane exchange of people while southerners the chance to gain more labor for their plantations.