Answer: d) the population found it nearly impossible to combat the spread of the plague.
The skeleton in the middle of the picture is meant to represent Death, and more specifically, Death brought on by the plague.
The plague, or the Black Death, was an epidemic of bubonic plague which reached England in 1348. Originating in China, the plague spread by flea-infected rats along the trade routes of Asia and Europe. Estimates of mortality provide a figure of 40-60% of the population of England. This high mortality rate was due to the inability of the population to combat the spread of the plague.