Which of the following works has Santiago as its protagonist?

The correct option is The old man and the sea.

Santiago is the central character and protagonist of Ernest Hemingway's Pulitzer Prize-winning 1952 novella, The Old Man and the Sea. He is an aging, experienced Cuban fisherman who struggles for three days in the Gulf Stream to catch a giant marlin, demonstrating endurance, dignity, and resilience in the face of nature and aging.

To provide context on why the other options are incorrect:
- Mansfield Park (by Jane Austen) has Fanny Price as its protagonist.
- The Mayor of Casterbridge (by Thomas Hardy) has Michael Henchard as its protagonist.
- The Lord of the Rings (by J.R.R. Tolkien) primarily features Frodo Baggins as the protagonist.