Explanation:

- Option 1: 1917

- Incorrect. By 1917, King George V was already crowned as the Emperor of India and played a significant role in World War I.

- Option 2: 1906

- Incorrect. At this time, George V was the Prince of Wales. He took on more duties as Edward VII's health waned.

- Option 3: 1923

- Incorrect. George V was already reigning as King during this year, having established his rule over a decade earlier.

- Option 4: 1911

- Correct. King George V was formally crowned as the Emperor of India in 1911. He and Queen Mary were the only British monarchs to attend the Delhi Durbar, marking the coronation.