Final answer:
The mass of one sheet of paper is best estimated at 1 gram, similar to the weight of a standard paperclip.
Step-by-step explanation:
The estimate for the mass of 1 paper is closest to Option A, which is 1 gram. A paperclip, which is a commonly used item for comparison in mass, weighs about 1 gram. By this benchmark, one sheet of paper would have a mass approximately equal to that of a paperclip. Additionally, other common units of mass like the milligram are too small for a sheet of paper; a milligram is a unit of mass used for items much lighter, like a speck of dust. Therefore, one sheet of paper is best estimated as 1 gram in mass.