This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
In a 32yr old male presenting with the following blood chemistry Na+-> 135, K+^> 5.0, HC03 ^ 14.0, Cl ^ 116, P04~-> 5.0, SO;-> 5.0, Mg++-> 2.0, Ca++^> 8.0 the anion gap is : 
Select and explain. 
A. 20, B. 15, C. 13, D. 10
D: 10
Answer: D: 10 
Explanation: . 10