Arrange the sequence of national events in the order of their occurrence.

(A) Swachh Bharat Abhiyaan

(B) Mars Orbiter Mission

(C) Right to Information Act

(D) Economic Liberalization

Choose the correct answer from the options given below:

The correct option is (D), (C), (B), (A).

To arrange these national events of India in the correct chronological order of their occurrence, let us look at the year each event took place:
1. (D) Economic Liberalization: India initiated major economic reforms and liberalization in the year 1991 under the leadership of Prime Minister P. V. Narasimha Rao and Finance Minister Dr. Manmohan Singh.
2. (C) Right to Information Act: The Right to Information (RTI) Act was enacted by the Parliament of India in the year 2005 to provide for setting out the practical regime of right to information for citizens.
3. (B) Mars Orbiter Mission: Also known as Mangalyaan, this space probe was launched by the Indian Space Research Organisation (ISRO) on 5 November 2013 and entered Mars orbit in September 2014.
4. (A) Swachh Bharat Abhiyaan: This nationwide cleanliness campaign was launched by the Government of India on 2 October 2014 to clean up the streets, roads, and infrastructure of India's cities, towns, and rural areas.

Arranging these years in ascending order:
1991 (D) → 2005 (C) → 2013 (B) → 2014 (A)

Therefore, the correct chronological sequence is (D), (C), (B), (A).