In the Canterbury Tales, what was the prize for telling the best tale? A. a horse B. a dinner or C a book?

The Canterbury Tales were written in 1386 by Geoffrey Chaucer. 

In the original language, the portion about the prize for the best tale reads: 

Tales of best sentence and most solas,

Shal have a soper at our aller cost

Here in this place, sitting by this post,

Whan that we come agayn fro Caunterbury.

Therefore, in the second line above, Chaucer writes that the inn keeper promises the person telling the best tale will have a dinner at no cost there in the Inn. The tales are told by a diverse group as they travel together. The inn keeper suggested that they tell the tales to pass the time, then suggested the prize for the best tale. As they travel together to Canterbury, each is to tell two tales and on the return trip, two more tales. Once back at the inn, the inn keeper will decide the winner.