Final answer:
B. 1.019 g. The unknown sample has a mass of 1.019 g (Option B).
Step-by-step explanation:
The unknown sample has a mass of 1.019 g (Option B).
To determine the mass of the unknown sample, we should select the option that provides the most accurate and precise measurement. Option B, 1.019 g, is the most precise as it includes three significant figures. The other options have either fewer or more significant figures, which indicates less precision.
Therefore, the correct answer is 1.019 g (Option B).