Step 1: About Ilbert Bill.
Ilbert Bill (1883) allowed Indian judges to try European offenders in India. It faced strong opposition from the Europeans.
Step 2: Options analysis.
(A) Lord Lytton: Before Ripon.
(B) Lord Ripon: Correct — Ilbert Bill was introduced in 1883 under Ripon.
(C) Lord Dalhousie: Wrong period (1848–1856).
(D) Lord Curzon: Wrong period (1899–1905).
Step 3: Conclusion.
Thus, the Ilbert Bill was passed under Lord Ripon.