Which of the following sentences is in the present perfect continuous tense?

$\mathrm{A}\left(\mathrm{g}\right)\rightleftharpoons 2 \mathrm{B}( \mathrm{g})+\mathrm{C}\left(\mathrm{g}\right)$

For the given reaction, if the initial pressure is $450 \mathrm{mmHg}$ and the pressure at time $\mathrm{t}$ is $720 \mathrm{mmHg}$ at a constant temperature$\mathrm{T}$ and constant volume $\mathrm{V}$. The fraction of $\mathrm{A}\left(\mathrm{g}\right)$ decomposed under these conditions is $\mathrm{x}\times {10}^{-1}$. The value of $\mathrm{x}$ is (nearest integer)

The following carbohydrate is

Consider the following radioactive decays

I. ${}_{92}\mathrm{U}{\stackrel{-\mathrm{\alpha }}{⟶}}_{90}\mathrm{Th}$ and

II. ${}_{90}\mathrm{Th}\stackrel{-\mathrm{\alpha }}{⟶}{}_{88}\mathrm{Ra}$

In which case group of parent and daughter elements remains unchanged.