Step 1: Understand the event.
The Chauri Chaura incident made Gandhi suspend the Non-Cooperation Movement. We need the state where it happened.
Step 2: The incident.
On 4 February 1922 protesters clashed with police at Chauri Chaura. The crowd set the police station on fire and many policemen died.
Step 3: The location.
Chauri Chaura is in the Gorakhpur district of present-day Uttar Pradesh.
Step 4: Rule out others.
Bihar is linked to Champaran, West Bengal to the Swadeshi movement, and Punjab to Jallianwala Bagh. None of these is Chauri Chaura.
Step 5: Conclude.
The incident took place in Uttar Pradesh.
Answer: Uttar Pradesh