Identify the correct way to write the following in exponential form.
6 x 6 x 6 x 6 x 6 x 6 x 6 x 6
6(8)
86
8 x 6
68
6 x 6 x 6 x 6 x 6 x 6 x 6 x 6
6(8)
86
8 x 6
68