Who kept a diary between 1660 and 1669 while serving as secretary at the Admiralty?

The correct choice is Samuel Pepys, who is renowned for his detailed diaries that provide a unique insight into life in 17th-century England. He maintained his diary from 1660 to 1669 while serving as a secretary at the Admiralty, where he documented significant events such as the Great Plague and the Great Fire of London, as well as his personal experiences and reflections.

Pepys's diaries are not only important historical documents but also notable for their literary style, offering a vivid portrayal of his thoughts, feelings, and the everyday life of his time. This makes them invaluable for researchers and historians studying that era. The diaries are often praised for their detail and clarity, establishing Pepys as a significant figure in the documentation of British history.

Other figures listed, such as John Evelyn, while also notable diarists, did not serve in the same capacity at the Admiralty nor maintained a diary with the same level of detail focused specifically on the government and naval affairs during that period. Samuel Johnson and Charles II are also historically significant but do not directly relate to the diary kept during the specified years and position as Pepys does.