The correct answer is option 2, Bal Gangadhara Tilak. Bal Gangadhara Tilak was a prominent Indian nationalist leader who played a crucial role in the Indian independence movement. He popularized the slogan "Swaraj is my birthright and I shall have it" during the freedom struggle. The phrase emphasized his belief that self-rule or independence is the inherent right of every Indian citizen.
Option 1, Gopal Krishna Gokhale, was a prominent social and political leader, but he did not declare this particular slogan.
Option 3, Lala Lajpat Rai, was also a prominent nationalist leader, but he is not associated with this specific slogan.
Option 4, K.T. Telang, is not a well-known figure in Indian history and is not relevant to this question.
In summary, Bal Gangadhara Tilak is the correct answer for declaring the slogan "Swaraj is my birthright and I shall have it."