Which reagent is used to convert Alkyl halide into Alkyl nitrite ?

Which of the following on reaction with Grignard's reagent followed by hydrolysis forms tertiary alcohol ?

Identify product 'B' in following series of reactions
2-methylpropan-2-ol $\xrightarrow[\large{363\ \text{K}}]{\large{20\%\ \text{H}_2\text{SO}_4}}$ A $\xrightarrow[\large{\text{Conc. H}_2\text{SO}_4}]{\large{\text{H}_2\text{O}\ \ \Delta}}$ B

Which among the following compounds has highest solubility in water?