Answer:

Step-by-step explanation:
Reduction:
- decrease in oxidation state.
Oxidation:
- increase in oxidation state.
In the reaction:

The oxidation state decreases from +5 to +2, which means there is a decrease in oxidation state. So, reduction has taken place.
![\rule[226]{226}{2}](https://img.qammunity.org/2023/formulas/chemistry/high-school/5kf7rvblfd92w57uei4vw3blhe92ijeghx.png)