From the following options which is/are correct for double chain silicates?

In double chain silicates,

$A\to 2^{\mathrm{\prime }}{O}^{\mathrm{\prime }}$ atoms are shared 

$\Rightarrow {\mathrm{SiO}}_{1+1+0.5+0.5}={\mathrm{SiO}}_3^{2-}B\to 3^{\mathrm{\prime }}{0}^{\mathrm{\prime }}$

atoms are shared $\Rightarrow$${\mathrm{SiO}}_{1+0.5+0.5}={\mathrm{SiO}}_{2.5}^{-}A+B\Rightarrow {\mathrm{Si}}_2{\mathrm{O}}_{55}^{3-}\text{ or }{\mathrm{Si}}_4{\mathrm{O}}_{11}^{6-}\Rightarrow$

Per silicate, charge  $=\frac{-6}{4}=-1.5$ No, of ' O ' atoms shared/silicate $=\frac{11}{4}=2.5$

Hence the correct answer is A,B,C