Answer:
Ohio
Step-by-step explanation:
Ohio was a Union state that did not allow slavery within its territories.
Maryland, Missouri, and Texas all allowed slavery, and found it to be very important to their societies and economies.
Ohio was created with the Northwest Ordinance of 1787.
This ordinance outlawed slavery in all of the states in the Northwest Territory, which Ohio was a part of.
So, the correct answer is Ohio.