Choose the correct statement(s) :

The correct options are
A $Ca{C}_2$ is formed by reacting $CaO$ with coke in presence of heat.
C Ethyne can be prepared from $Ca{C}_2$ by reacting it with $H_{2}O$ in presence of heat
D Vicinal dihalides on treatmentwith alcoholic KOH undergo dehydrohalogenation.
Preperation of $Ca{C}_2$ :
$CaC{O}_3\stackrel{\Delta }{⟶}CaO+C{O}_2$
$CaO+\underset{Coke}{3C}\stackrel{\Delta }{⟶}Ca{C}_2+CO$

Industrial method of preperation of ethyne :
$Ca{C}_2+2H_{2}O\stackrel{\Delta }{⟶}Ca(OH{)}_2+\underset{\text{Ethyne}}{C_2{H}_2}$

Preperation of alkynes from vicinal dihalides :
Vicinal dihalides on treatment with alcoholic $KOH$ undergo dehydrohalogenation. One molecule of $HX$ is eliminated to form alkenyl halide which on treatment with sodamide gives alkyne.