In Narrative of the Life of Frederick Douglass, An American Slave, what does Douglass say is the role of the holidays in the institution of slavery?

a. The holidays are seen as a good time for slaveowners to free some of their slaves.
b. The holidays are the only times that slaves are allowed to see their extended family, and this provides them with enough comfort and strength to make it through the year.
c. The freedoms given to slaves during the holidays increase their desire to run away, and thus holiday celebrations are harshly curtailed by slaveowners.
d. The freedoms given to slaves during the holidays only strengthen the institution of slavery, because those liberties allow for a "safe outlet" for any rebellious sentiments.