E6A12 (D) 
Why do many MOSFET devices have built-in gate-protective Zener diodes?
A. To provide a voltage reference for the correct amount of reverse-bias gate voltage
B. To protect the substrate from excessive voltages
C. To keep the gate voltage within specifications and prevent the device from overheating
D. To reduce the chance of the gate insulation being punctured by static discharges or excessive voltages
