From the following masses, the one which is expressed nearest to the milligram is
A. 16 g
B. 16.4 g
C. 16.428 g
D. 16.4284 g

Hint: Measurement of mass is described by a number and then the units in which it is computed. Gram is a unit that is used to express mass. It is denoted by the symbol g. The milligram is denoted by the symbol mg: 1 g = 1000 mg.

Complete Step by Step Solution:
Each subject carries a specific characteristic. These properties can be divided into two types.
1. Physical properties like colour, odour, melting point, boiling point, density, etc., can be observed without any change in the composition of the substance.
2. Chemical properties like composition, combustibility, activity with acids and bases, etc., need a chemical change to be calculated.

Mass is a physical property. Measurement of mass is described by a number and then the units in which it is computed. For example, 60g in which 60 gives the quantity and gram is the unit.
We know that 1 g = 1000 g.
So, 1 g = 1000 mg
We are given different masses, we have to find out the one which is expressed nearest to the milligram is
A. 16 g = 1600 mg
B. 16.4 g = 1640 mg
C. 16.428 g = 16428 mg
D. 16.4284 g = 16428.4 mg
For option C, all the digits involved are significant figures and are also nearest to the milligram.
So, option C is correct.

Note: Significant numbers are nothing but the numbers that possess certainty.
For example, the length of cloth is 4.567m where digit 4 is known with certainty.
The digits after the decimal point have no certainty as we do not know about the values.
In the given question, the 16428 mg value has five significant numbers as the non-zero digits have significance.