What did Missouri, Kentucky, Maryland, and Delaware have in common during the Civil War?

Question

A.They all declared their neutrality during the war.***
B.They were all slave states that had remained in the Union.
C. They were the first Confederate states to be captured by the Union army.
D.They freed their slaves before the Emancipation Proclamation was issued.

Check answer please!!

Answer 1

Actually I change my answer, is it B??

Answer 2

B is correct. :)

Answer 3

im confused