Is the Synthesis of Ozone $\mathrm { O } _ { 3 }$

Multiple Choice

Is the synthesis of ozone, $\mathrm { O } _ { 3 }$ ,from oxygen, $\mathrm { O } _ { 2 }$ ,an example of an exothermic or endothermic reaction?

A) exothermic because ultraviolet light is emitted during its formation
B) endothermic because ultraviolet light is emitted during its formation
C) exothermic because ultraviolet light is absorbed during its formation
D) endothermic because ultraviolet light is absorbed during its formation