Final answer:
Dante Alighieri's use of the Tuscan dialect in the 'Divine Comedy' helped make it the standard form of modern Italian.
Step-by-step explanation:
The correct answer is a) Dante Alighieri. Dante Alighieri's use of the Tuscan dialect in the 'Divine Comedy' helped make it the standard form of modern Italian. Written in the 14th century, the 'Divine Comedy' is an epic poem that describes Dante's journey through Hell, Purgatory, and Heaven. Dante's choice to write in the Tuscan dialect, which was his native language and spoken in Florence, Italy, played a crucial role in establishing Tuscan as the foundation for the Italian language.