The electronic configuration of $$\mathrm{Cu}(\mathrm{II})$$ is $$3 \mathrm{~d}^9$$ whereas that of $$\mathrm{Cu}(\mathrm{I})$$ is $$3 \mathrm{~d}^{10}$$. Which of the following is correct?

In which one of the following pairs the central atoms exhibit $$\mathrm{sp}^2$$ hybridization ?

Relative stability of the contributing structures is :

Correct order of basic strength of Pyrrole , Pyridine and Piperidine is :