Answer
The best estimate for the weight of a nickel is: b. 5 g
Work Step by Step
Clearly 5 kg seems too heavy for the weight of one nickel, and 5 mg seems too light.
One mL of water weighs one gram. Since one tsp of water is about 5 mL,, a weight of 5 grams is the weight of one tsp of water. This seems reasonable for the weight of a coin.
The best estimate for the weight of a nickel is: b. 5 g