Explanation:

- King George V assumed the crown of India in 1911 during the Delhi Durbar, where he was proclaimed Emperor of India.

- Option 1: 1917 – This is incorrect; by 1917 he was already Emperor, and this year is notable for events in World War I.

- Option 2: 1906 – Incorrect, as King George V was not yet king; his father, Edward VII, was still on the throne.

- Option 3: 1923 – Also incorrect; by then, he had already been Emperor for over a decade.

- Option 4: 1911 – This is the correct answer. King George V held the Delhi Durbar in December 1911, formally assuming the title of Emperor of India.