Answer:
B) One sheet of paper is 0.0042 inches thick
Explanation:
All the other values are not give from just a sheet of paper, and/or they are either a cumulative value, or values that will be used to calculate another value
Only option B defines a value for a unit of paper, and the value is definite.
Option A indicates the number in a group (gross)
Option C shows two values that can be used to calculate one value; the area.
Option D indicates an accumulated value of weight.