Step 1: Overview of Nepal's Democratic Movement.
Nepal formally established democracy in 2008 after years of political instability, including the abolition of the monarchy. The 2006 People's Movement, known as the Jana Andolan, played a key role in this transition.
Step 2: Analysis of options.
- (A) 2002: This was a period of political unrest, but democracy was not yet fully established.
- (B) 2004: Democracy had not yet been fully established in Nepal.
- (C) 2006: The 2006 People's Movement led to significant political changes but not full establishment of democracy.
- (D) 2008: In 2008, Nepal formally became a federal democratic republic after the monarchy was abolished.
Step 3: Conclusion.
Nepal officially established its democratic republic in 2008, making the correct answer (D) 2008.