One of the following is an endothermic reaction. This is 

The formation of nitric oxide from the reactants ${\text{N}}_{\text{2}}$ gas and ${\text{O}}_{\text{2}}$gas.

${\text{N}}_2\left(\text{g}\right)+{\text{O}}_2\left(\text{g}\right)+\text{\hspace{0.17em}\hspace{0.17em}Q\hspace{0.17em}}\to 2\text{NO}\left(\text{g}\right)\text{;\hspace{0.17em}\hspace{0.17em}}\Delta \text{H\hspace{0.17em}}=+\text{ve\hspace{0.17em}\hspace{0.17em}}\&\text{\hspace{0.17em}Endothermic}$

The formation of Co from the reactants C and $O_2$ gas

 $2C_{\left(s\right)}+O_{2\left(g\right)}\to 2C{O}_{\left(g\right)},\Delta H=-ve$ and exothermic the formation of $C{O}_2$ and $H_{2}O$ from glucose and $O_2$

 $C_6{H}_{12}{O}_{6\left(s\right)}+6O_{2\left(g\right)}\to 6C{O}_2+6H_{2}O,\Delta H=-ve$ and exothermic. The formation of zinc chloride and $H_2$ from Zn and HCl. $Z{n}_{\left(s\right)}+2HC{l}_{\left(aq\right)}\to ZnC{l}_{2\left(aq\right)}+H_{2\left(g\right)},\Delta H=-ve$ and exothermic.