Final answer:
Pecorino Romano is the correct answer as it is the cheese mentioned by Pliny the Elder in his historical writings. This hard Italian cheese is known for its salty flavor and use in grating over pasta.
Step-by-step explanation:
The cheese that Pliny the Elder wrote about is Pecorino Romano. Pliny the Elder was a Roman author and natural philosopher who mentioned Pecorino Romano in his encyclopedic work, 'Naturalis Historia,' highlighting its importance in the diet of the Roman legions. Pecorino Romano is a hard, salty Italian cheese, made out of sheep's milk and widely used for grating over pasta dishes.
Historically, the cheese comes from the region around Rome, and its production can be dated back more than 2,000 years. Today, it continues to be a popular ingredient in Italian cuisine and can be found in many other parts of the world owing to its distinctive flavor profile that enriches a variety of recipes.