Answer:
Option d.
Step-by-step explanation:
The nth root of the product of the n observations is the geometric mean.
Geometric mean uses the product of values of the data set to indicate the central tendency of the data set.
For a set [tex]\left \{ x_1,x_2,x_3,...,x_n \right \}[/tex], geometric mean is defined as [tex]\sqrt[n]{x_1x_2x_3...x_n}[/tex] i.e., [tex]\left ( \prod_{i=1}^{n}x_i \right )^{\frac{1}{n}}[/tex]
Here, the symbol [tex]\prod[/tex] denotes multiplication.
Therefore, option d, is correct.