Which of the following is a correct representation of inclusion-exclusion principle?

• A. |A U B|=|A|+|B|-|A,B|
• B. |A,B|=|A|+|B|-|A U B|
• C. |A U B|=|A|+|B|+|A,B|
• D. |A,B|=|A|+|B|+|A U B|