In $$\text{YBa}_2\text{Cu}_3\text{O}_{7-x}$$, a superconducting oxide that got George Bednorz and Karl Muller the Nobel prize in 1986, Cu can exist in both $$+2$$ and $$+3$$ oxidation states and their proportion depends on the value of x. In $$\text{YBa}_2\text{Cu}_3\text{O}_{6.5}$$

A

0.5 moles of Cu are in $$+3$$ oxidation state

B

5% of Cu is in $$+3$$ oxidation state

C

All the Cu is in $$+3$$ oxidation state

D

All Cu is in $$+2$$ oxidation state