Extensions of C*-algebas by a small ideal

We classify all essential extensions of the form $$0\to \text{W}\to \text{D}\to A\to 0$$ where $\text{W}$ is the unique separable simple C*-algebra with a unique tracial state, with finite nuclear dimension and with $K_i(\text{W})=\{0\}$ ($i=0,1$) which satisfies the Universal Coefficient theorem (UCT), and $A$ is a separable amenable $\text{W}$-embeddable C*-algebra which satisfies the UCT. We actually prove more general results. We also classify a class of amenable \CA s which have only one proper closed ideal $\text{W}\mathrm{.}$