g(x) is 2x²
this is so because.
when x= 2
g(x)= 2×2²=2×4=8
also when x= (-2)
g(x) =2×(-2)²=2×4=8
Also as per the graph. (1,2) and (-1,2) lies on g(x)
when x=1
g(x) =2(1)²=2
when x=(-1)
g(x) =2(-1)²=2
Other Ootion will not give correct result for (1,2),(-1,2) ,(2,8),(-2,8)
Hope it helps...
Regards;
Leukonov/Olegion.