Which answer matches this clue: the clay-court tennis tournament held at the Foro Italico, one of the nine ATP Masters 1000 events?

• A Monte-Carlo Masters
• B Madrid Open
• C Internazionali d'Italia ✓
• D Hamburg Open

The Italian Open has been held since 1930 and is played at the Foro Italico complex, known for its neoclassical architecture and statue-lined courts.