Answer:
A). That people of African descent are no less human than white settlers and should be treated respectfully.
Step-by-step explanation:
As per the question, in the given excerpt from "The Selling of Joseph" by Samuel Sewall, the author(Sewall's) assertion is that "African people are no less human and deserve equal respect and freedom' which is reflected by his descriptions like 'they are the sons and daughters of the First Adam', 'offspring of god' and when he says ''ought to be treated with respect agreeable". The author intends to denounce the evil practice of slavery(African especially) and its after-effects in Africa. Therefore, option A is the correct answer as the author demands equal rights and respect for them.