Which of the Following Examples Would Most Accurately Measure the Density

Which of the following examples would most accurately measure the density of the population being studied?

A) counting the number of prairie dog burrows per hectare
B) counting the number of times a 1 kilometer transect is intersected by tracks of red squirrels after a snowfall
C) counting the number of coyote droppings per hectare
D) multiplying the number of moss plants counted in 10 quadrats of 1m² each by 100 to determine the density per kilometer².
E) counting the number of zebras from airplane census observations.