Which of the following shows logarithmic function?
a.
[tex]f(x) = 8 {x}^{3} + 8[/tex]
b.
[tex]f(x) = log \: 9 \: 81[/tex]
c.
[tex]f(x) = |3 {}^{x} - 6| [/tex]
d.
[tex]f(x) = | |x - 1| | - 8[/tex]
​