How should the architect fix this problem?

Universal Containers (UC) has a custom Apex class that enforces a business process and updates opportunity field-level security permissions of read only certain user’s profiles are being updated by their class.

How should the architect fix this problem?
A . Put the code in an class that uses the With Sharing keyword.
B. Use the IsUpdateable() Apex method to test each field prior to allowing updates.
C. Use the With SECURYT_ENFORCED keyword in the SOQL statement.
D. Add With Sharingkeyword to the class.

Answer: C