The correct answer is option 3, Robert Walpole. Oliver Cromwell, mentioned in option 1, was not a Prime Minister of England. He was a military and political leader who became the Lord Protector of the Commonwealth of England, Scotland, and Ireland in the mid-17th century. Benjamin Disraeli, mentioned in option 2, was a significant political figure in the 19th century but he served as Prime Minister of the United Kingdom, not specifically England. Option 4, Gladstone, is incorrect as well. William Ewart Gladstone was a prominent British statesman and served as Prime Minister multiple times in the 19th century, but he was not the first Prime Minister of England. Robert Walpole, mentioned in the correct answer, is considered the first Prime Minister of England. He served as the Prime Minister from 1721 to 1742 and is regarded as the longest-serving Prime Minister in British history.