Introduction:
National Youth Day is observed in India every year to commemorate the birth anniversary of Swami Vivekananda, who was a great philosopher, thinker, and youth icon. This day is celebrated to encourage and inspire the youth of the nation to work towards the betterment of society and to promote the ideals and teachings of Swami Vivekananda.

Date of National Youth Day:
The correct answer is option 'D', January 12. National Youth Day is observed in India on January 12th every year. This date was chosen to honor the birth anniversary of Swami Vivekananda, who was born on January 12, 1863, in Kolkata, India.

Significance of January 12:
Swami Vivekananda was an influential figure in the Indian independence movement and played a crucial role in spreading Vedanta philosophy and the teachings of Hinduism to the Western world. He believed in the potential of the youth and their ability to bring about positive changes in society. Swami Vivekananda's teachings and ideas continue to inspire and motivate the youth of India.

Celebrations and Activities:
On National Youth Day, various events and activities are organized across the country to engage and empower the youth. These include:

1. Speeches and Seminars: Public speeches and seminars are conducted where eminent speakers discuss the life, teachings, and philosophy of Swami Vivekananda.

2. Youth Conferences: National and regional youth conferences are organized to provide a platform for the youth to express their ideas, discuss social issues, and come up with innovative solutions.

3. Competitions: Essay writing, elocution, and debate competitions are held in schools, colleges, and universities to encourage the youth to showcase their talents and express their thoughts on relevant topics.

4. Cultural Programs: Various cultural programs, including music, dance, and drama, are organized to promote talent and creativity among the youth.

5. Social Service Activities: Voluntary blood donation camps, cleanliness drives, and other social service activities are conducted to instill a sense of responsibility and compassion among the youth.

6. Workshops and Skill Development Programs: Workshops and training programs are conducted to enhance the skills and knowledge of the youth in areas such as leadership, entrepreneurship, and career development.

Conclusion:
National Youth Day is observed in India on January 12th every year to honor the birth anniversary of Swami Vivekananda. This day serves as a reminder of his teachings and philosophy, inspiring the youth to become responsible citizens and contribute positively to society. Through various events and activities, National Youth Day encourages the youth to channel their energy and potential towards nation-building and social progress.