Please answer the following question: Generate a question that has the following answer: the popular liqueur for the following movie plot: Brother George (Walter Chiari) is the only monk at the Italian Monastery who knows the secret recipe of the popular liqueur that is the sole source of income for the monastery. When he feels their sole distributor, a local wine merchant, isn't giving the Monastery a fair price, he leaves and moves to Australia. There he works at a vineyard picking grapes and starts making the Liquor in his spare time. George then comes to the attention of the Winery owner Alfredo Brazzi (Jack Albertson) and the two agree to a partnership to make the liqueur. Alfredo is unaware George is a monk and that he sends 50% of the money back to his Italian monastery. Alfredo and his son-in-law Tim (Dave Allen) constantly try to steal the secret recipe. They recruit June (Rowena Wallace) for their skulduggery, but she falls in love with George, also unaware of his religious calling. Finally, the Italian wine merchant travels to Sydney, willing to make a deal with Brother George. The merchant ends up paying double the price he had previously rejected in this amusing comedy.Spoiler - In a dash for the cash, George hits his head and forgets the recipe.
A:
what is the sole source of income for the monastery?