$\underbrace{HgI_2}_{X}$ $\xrightarrow[\text{Sublimation}]{\Delta} \underbrace{HgI_2}_{Y}$ $\xrightarrow[\text{On rubbing}]{\text{Cooling}} \underbrace{HgI_2}_{Z}$

• A
  $'X'$ $\rightarrow \text{Yellow}, 'Y'$ $\rightarrow \text{Red}, 'Z'$ $\rightarrow \text{Yellow}$
• B
  $'X'$ $\rightarrow \text{Red}, 'Y'$ $\rightarrow \text{Yellow}, 'Z'$ $\rightarrow \text{Red}$
• C
  $'X'$ $\rightarrow \text{Red}, 'Y'$ $\rightarrow \text{Yellow}, 'Z'$ $\rightarrow \text{Yellow}$
• D
  $'X'$ $\rightarrow \text{Yellow}, 'Y'$ $\rightarrow \text{Red}, 'Z'$ $\rightarrow \text{Red}$