The factors of 28 are: 1, 2, 4, 7, 14, 28.
The number of factors = 6.
The product of all factors is given by:
\[ (\text{Product of factors}) = (\text{Number})^{\frac{\text{Total factors}}{2}} \]
\[ 28^{\frac{6}{2}} = 28^3 \]
\[ 28^3 = 21,952 \]
Thus, the correct answer is 21,952 (Option A).