The correct answer for the question that is being presented above is this one:
We need to express the ksp expression of C2D3
C2D3
= (2x)2(3x)3
= 108x5
Then set that equation equal to your solubility constant
9.14x10-9 = 108x5
x = 9.67x10-3
So the molar solubility is 9.67x10-3