The correct answer is option 3, Lord Dufferin. The Indian National Congress was founded during his tenure as the Viceroy of India.

To understand why this option is correct, let`s briefly look at the other options. Option 1, Lord Lytton, served as the Viceroy from 1876 to 1880 and is known for the implementation of the famous Vernacular Press Act, but it is not associated with the founding of the Indian National Congress. Option 2, Lord Ripon, served as the Viceroy from 1880 to 1884 and is associated with the introduction of various reforms such as the local self-government and the Ilbert Bill, but he did not play a role in the founding of the Indian National Congress. Option 4, Lord Mayo, served as the Viceroy from 1869 to 1872 and was assassinated during his tenure, but he also did not contribute to the establishment of the Indian National Congress.

Therefore, the correct answer is option 3, Lord Dufferin, who served as the Viceroy from 1884 to 1888 and witnessed the formation of the Indian National Congress in 1885.