Choose the correct statements from the following

A. $\mathrm{Mn}_2 \mathrm{O}_7$ is an oil at room temperature

B. $\mathrm{V}_2 \mathrm{O}_4$ reacts with acid to give $\mathrm{VO}_2{ }^{2+}$

C. $\mathrm{CrO}$ is a basic oxide

D. $\mathrm{V}_2 \mathrm{O}_5$ does not react with acid

Choose the correct answer from the options given below :