Respuesta :

[tex]a_3=a_1r^2=108[/tex]
[tex]a_5=a_1r^4=972[/tex]

[tex]\implies\dfrac{a_5}{a_3}=\dfrac{a_1r^4}{a_1r^2}\iff\dfrac{972}{108}=r^2\implies r=\pm\sqrt9=\pm3[/tex]

[tex]a_8=a_1r^7=a_5r^3=972(\pm3)^3[/tex]

Judging by the given choices, the common ratio is likely the positive candidate, so

[tex]a_8=972(3)^3=26244[/tex]

so the answer is C.