Which of the following alkenes does $\underline{NOT}$ exhibit cis-trans isomerism?

What is $X$ in the given reaction?
$HOCH_2-CH_2OH + (COOH)_2 \xrightarrow{210^{\circ}C} X$
(major product)

Identify the type of the given reactions:
$(a) \ CH_3CH_2OH \xrightarrow[\Delta]{\text{Conc. } H_2SO_4} CH_2 = CH_2 + H_2O$
$(b) \ CH_2BrCH_2Br + Zn \xrightarrow{\Delta} CH_2 = CH_2 + ZnBr_2$
$(c) \ CH_3CHBr - CH_2Br + Zn \xrightarrow{\Delta} CH_3CH = CH_2 + ZnBr_2$
$(d) \ RC \equiv CR' + H_2 \xrightarrow{Na, \text{liquid } NH_3} RCH = CHR'$
$(e) \ CH_3CH_2Cl + KOH \xrightarrow{\text{ethanol, } KOH} CH_2 = CH_2 + KCl + H_2O$

Ethylene reacts with Baeyer's reagent to give

The reaction of $3$-phenylpropene with $HBr$ gives (as the major product):

The alkene which on ozonolysis yields acetone is