Final answer:
In the musical 'Oklahoma!', Will wins $50 as the first prize at the fair, which is not related to the lottery winnings discussed in the excerpts provided.
Step-by-step explanation:
The first prize that Will wins at the fair in Oklahoma! isn't related to any of the events specified in the provided excerpts.
These excerpts from a different text discuss lottery winnings and not the prize won by a character named Will in the musical Oklahoma!.
To accurately answer the student's question from the musical, Will wins a $50 at the fair, which he uses to convince Ado Annie's father that he can support her (Option a).
The other options given in the question (a blue ribbon, a horse, and a gold watch) are not correct in the context of the musical Oklahoma!.