Chalcogen group elements are :

Statement I : $\alpha$ and $\beta$ forms of sulphur can change reversibly between themselves with slow heating or slow cooling.

Statement II : At room temperature the stable crystalline form of sulphur is monoclinic sulphur.

In the light of the above statements, choose the correct answer from the options given below:

Among the following, the number of halide(s) which is/ are inert to hydrolysis is

(A) ${\mathrm{BF}}_3$
(B) ${\mathrm{SiCl}}_4$
(C) ${\mathrm{PCl}}_5$
(D) ${\mathrm{SF}}_6$