Which among the following events happened earliest?

To determine which event occurred earliest, let us examine the specific year in which each of the given historical events took place:

1. Dinabandhu Mitra wrote Neeldarpan: The Bengali play Nil Darpan (The Indigo Mirror), which highlighted the plight of indigo farmers, was written in 1858–1859 and published in 1860.
2. Satyendranath Tagore became the first Indian to succeed in the Indian Civil Services Examination: Satyendranath Tagore passed the Indian Civil Services (ICS) examination in 1863.
3. Swami Dayanand established Arya Samaj: The Hindu reform movement Arya Samaj was founded by Swami Dayanand Saraswati in Bombay on April 10, 1875.
4. Bankim Chandra Chattopadhyay wrote Anandmath: The celebrated novel Anandamath was published in 1882.

Comparing the years of these events:
• Neeldarpan: 1858–1860
• Satyendranath Tagore in ICS: 1863
• Arya Samaj established: 1875
• Anandmath written: 1882

Therefore, the event that happened earliest is that Dinabandhu Mitra wrote Neeldarpan.

The correct option is Dinabandhu Mitra wrote Neeldarpan.