Which of the following is incorrect?

The correct option (the incorrect reaction) is shown in the second image:
$${\mathrm{CH}}_3\−C{\left({\mathrm{CH}}_3\right)}_2\−\mathrm{OH}\underset{573\text{\ K}}{\overset{\mathrm{Cu}}{\→}}{\left({\mathrm{CH}}_3\right)}_{2}C=O+{\mathrm{CH}}_4$$

Explanation of why this reaction is incorrect:
When primary or secondary alcohols are passed over heated copper ($\mathrm{Cu}$) at $573\text{\ K}$, they undergo dehydrogenation (loss of hydrogen) to form aldehydes and ketones, respectively.
However, tertiary alcohols (such as 2-methylpropan-2-ol, or tert-butyl alcohol, shown in the image with methyl groups attached to the central carbon carrying the $\−\mathrm{OH}$ group) do not have an $\mathrm{\α}$-hydrogen atom. Since dehydrogenation is not possible, tertiary alcohols undergo dehydration (loss of a water molecule) under these conditions.

Therefore, the reaction of tert-butyl alcohol with heated copper at $573\text{\ K}$ yields 2-methylpropene (isobutylene) and water, rather than acetone and methane. The correct chemical equation is:
$${\left({\mathrm{CH}}_3\right)}_{3}C\−\mathrm{OH}\underset{573\text{\ K}}{\overset{\mathrm{Cu}}{\→}}{\left({\mathrm{CH}}_3\right)}_{2}C={\mathrm{CH}}_2+H_{2}O$$

Analysis of the other reactions:
1. First reaction (Image 0): Ethanol (${\mathrm{CH}}_3\−{\mathrm{CH}}_2\−\mathrm{OH}$) reacts with concentrated $H_2{\mathrm{SO}}_4$ at $443\text{\ K}$ to undergo dehydration, producing ethene (${\mathrm{CH}}_2={\mathrm{CH}}_2$) and water. This reaction is correct.
2. Third reaction (Image 2): Propan-2-ol (${\mathrm{CH}}_3\−\mathrm{CH}\left(\mathrm{OH}\right)\−{\mathrm{CH}}_3$) undergoes dehydration in the presence of $\mathrm{85\%}\text{\ }{H}_3{\mathrm{PO}}_4$ to form propene (${\mathrm{CH}}_3\−\mathrm{CH}={\mathrm{CH}}_2$) and water. This reaction is correct.
3. Fourth reaction (Image 3): Ethanol (${\mathrm{CH}}_3\−{\mathrm{CH}}_2\−\mathrm{OH}$), a primary alcohol, is dehydrogenated over heated copper at $573\text{\ K}$ to yield acetaldehyde (${\mathrm{CH}}_3\mathrm{CHO}$) and hydrogen gas ($H_2$). This reaction is correct.