Option 1: (A), (D), (B), (C) -> "who is a doctor, my brother Jagan, for his higher studies has gone to America" - grammatically incorrect, starts with a relative clause.
Option 2: (B), (C), (D), (A) -> "for his higher studies has gone to America my brother Jagan, who is a doctor" - incorrect structure, subject comes too late.
Option 3: (D), (A), (C), (B) -> "My brother Jagan, who is a doctor, has gone to America for his higher studies" - grammatically correct with proper subject-verb agreement and logical flow.
Option 4: (C), (A), (D), (B) -> "has gone to America who is a doctor, my brother Jagan, for his higher studies" - starts with verb without subject, incorrect.
Hence, Option 3: (D), (A), (C), (B) -> The sentence follows the correct structure: subject (my brother Jagan) + relative clause (who is a doctor) + verb phrase (has gone to America) + purpose phrase (for his higher studies), creating a complete and meaningful sentence -> correct