The correct answer is B) so that the slaves could be presented as quality chattel.
Slavers fed and cleaned the slaves before the slaves were put on an auction block so that the slaves could be presented as quality chattel.
After a long trip from Africa under the most terrible conditions, the slavers tried to present the slaves as a valuable property to have a better sale. Slaves traveled in extremely overcrowded places for days, many got diseases and some died in the trajectory. When they finally arrived to be sold in the slave's auctions, slavers fed and cleaned them present them as good products. Let's remember that salves were not considered humans but property.