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: Medicine
A patient has normal PT and Platelet Count. The aPTT is increased and factor VIII levels are observed to be 60 lukIL (60%). There is no associated history of bleeding even after a surgical procedure. The most likely diagnosis is: 
Select and explain. 
A. Factor IX deficiency, B. Factor VIII inhibitors, C. Lupus anticoagulant, D. Thalassemia
C: Lupus anticoagulant
Answer: C: Lupus anticoagulant 
Explanation: Answer is C (Lupus Anticoagulant) Isolated prolongation of aPTT with no clinical history of bleeding suggests the presence of Lupus anticoagulant or deficiency of contact factors (Factor XII, Prekallikrein or HMWK)