Hey there :)
We know the area formula of a cone:
Area = [tex] \pi (radius)(lateral)+ \pi (radius)^2[/tex]
We are given the:
Radius = 6 units
Slant height = 15 units
Apply the formula!
A = [tex] \pi (6)(15)+ \pi (6)^2[/tex]
= [tex]90 \pi + 36 \pi [/tex]
= [tex] 126\pi [/tex] units²
Your answer will be option A