Step 1: Understanding the term "Persona non grata''
- This Latin term literally means "an unwelcome person.''
- In diplomacy, it refers to a diplomat who is declared unacceptable or undesirable by the host country.
- When a diplomat is declared "persona non grata,'' they are usually asked to leave the country.
Step 2: Why other options are incorrect
- (A) Being ungrateful is not related to the formal diplomatic term.
- (B) Inefficiency is not the meaning of "persona non grata.''
- (D) Being most desirable is the opposite of the term.
Step 3: Importance
- The term is a formal diplomatic tool used to express displeasure or rejection without breaking diplomatic relations outright.
Hence, option (C) correctly defines "persona non grata.''