Final answer:
Option (B), Article IV's Clause 3 of the U.S. Constitution, known as the fugitive slave clause, allowed for the return of escaped slaves to their owners and is rendered null by the 13th Amendment.
Step-by-step explanation:
Article 6 and Fugitive Slaves
You asked about the provisions made for fugitive slaves in Article 6. However, it seems there is a slight confusion in your question since the relevant article concerning fugitive slaves is Article IV of the Constitution, not Article 6. Specifically, Clause 3 of Article IV, which is known as the fugitive slave clause, addressed the issue of fugitive slaves. This clause allowed slave owners to reclaim escaped slaves from free states where they had sought refuge. Thus, the correct answer to your question is B: Allowed for their return to their owners, even in free states.
The Fugitive Slave Law of 1793 and the Compromise of 1850, with its harsher fugitive slave law, reinforced this constitutional provision. It was not until the 13th Amendment was adopted that this clause was rendered null and void, permanently banning slavery.