The answer would be "large or bulky" alligator. I say this because this word fits best. Hope this helps!
Capable, astute
Douglass describes Mrs Auld as apt, and follows up on this definition by showing how she took her husbands advice and mixed with her own experience made a strong and smart conclusion about slavery and education. This shows that she is smart and capable of doing much.
Second option because it states facts. Have a good day!
The answer is definitely B