Identify correct statements from the following 

A) ${\mathrm{MnF}}_7$  does not exist

B) ${\mathrm{MnO}}_3\mathrm{F}$ will exist

C) ${\mathrm{V}}_2{\mathrm{O}}_5$ is amphoteric with more acidic character

D) ${\mathrm{CrO}}_3$ is covalent

A) ${\mathrm{MnF}}_7$ . . . . does not exist

B) ${\mathrm{MnO}}_3{\mathrm{F}}_{ }$  . . . .  can exist…oxygen has the ability to form pi bonds

C) ${\mathrm{V}}_2{\mathrm{O}}_5$ . . . .  amphoteric (more acidic)

D) ${\mathrm{CrO}}_3$ . . . . covalent (group number oxidation state)