Why does the factor V Leiden mutation increase thrombotic risk?

a. Makes factor Va resistant to degradation by activated protein C
b. Makes blood more viscous
c. Makes factor V more susceptible to activation by thrombin
d. Decreases the binding of factor Va to the inhibitor antithrombin

ANS: A
Activated factor V Leiden is resistant to degradation by activated protein C, which is critical for slowing down thrombin generation. This results in an increased thrombotic risk for the patient.