Yes they wrote in the letter:"Immigration purpose other than Citizenship" is the correct option.
Why PCC from Canada is required? Does the request letter mentions PCC is needed for India and Canada?
Police Certificates (Multiple): You are required to provide a copy of your original police certificate from INDIA and any other country where you have resided for a period of six months or longer since the age of 18.
My parents resided earlier for 2 years in Canada from 2017 to 2019 and they came back last July 2022 on their Super Visa so I guess I will have to provide from Canada as well.