Answer:
14th amendment
Step-by-step explanation:
The 13 amendment would be the incorrect answer because that prohibits slavery and doesn't have relevance to this case. The 14 amendment is correct because that is the equal protection amendment and would definitely be relevant and help Marshall's argument. The 15 amendment is incorrect because that is the amendment that grants African American men the right to vote. It has no relevance to the case. The 24 amendment is incorrect because it is the right to not be denied the right to vote if you don't pay a fine or poletax.
Hope this helps! :)