You are working with delimited flat files and want to enforce a primary key on a flat file by using a Check Knowledge Mo

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You are working with delimited flat files and want to enforce a primary key on a flat file by using a Check Knowledge Modules (CKM). However, you encounter an error.Why did this happen?(Choose the best answer.)

A. It is not possible to enforce constraints on some technologies such as flat files and Java Messaging Service (JMS) queries.
B. It is not possible to enforce constraints on any technology.
C. It is only possible to forward-engineer it to the flat file definition.
D. It is possible to enforce a primary key on a flat file by using a CKM; however, you have to save it as a fixed file.