Which of the Following Is a Plausible Explanation for Slavery

Which of the following is a plausible explanation for slavery not being strictly outlawed in the Constitution?

A) Protections or slavery were upheld by a log roll of votes from northern states in return for strong commercial policies.
B) Slavery was viewed as a moral issue and was not seen as pertinent to the Convention's cause.
C) Slavery had already been abolished by most states so the Convention did not see the need.
D) Most of the delegates felt as though slavery would be replaced within the decade by itself.