Answer:

Step-by-step explanation:
The 10 Percent Plan was introduced by President Lincoln after the Civil War during the period of Reconstruction in the South. It outlined the rules for former Confederate states to rejoin the Union.
The main regulation was 10% of the voters needed to take an oath of loyalty to the Union, then the state could create new state governments with new state constitution including emancipation and the abolishment of slavery.
So, the voters didn't have to be previously loyal (A), free only 10% of the slaves (B), or have 10% freedmen voters (D). It involved pledges, or making promises, so C is correct.