Do you agree that ensuring best quality of products or services is core responsibility of quality assurance, quality control and production department?

It;s tough to agree with the statement. Quality is the overall result of the entire teamwork of the organisation of a whole. The benefit of efficient and effective methods being followed by one department can be nullified by a below average or destructive methods of other depatments. The purchase department have to ensure that the right materials are being bought and stored with least damages. The marketing department has to see that the marketing efforts are at par excellence in both sales as well as after sales. The facilities department have to ensure the right ergonomical measures are employed and so on and so forth. Each and every person in the organisation has to see to it that the standards being set by the quality departments are being followed without fail.

definatly

I don't agree because there are other departments has responsibility as procedures of ISO systemlike supply chain, Inventory and Planning departments as example