Correct option is (a) True
The explanation is: Dealing with guided weapons system such as missiles and laser-guided bombs the accuracy of HMD is adequate enough but for unguided weapons such as guns, unguided bombs, and rockets the accuracy is not yet feasible since the HMD is constantly moving with the pilots head. Currently, the boresight angles for HMD are 8 to 10 mRad, whereas for HUD it is 1.5 to 2 mRad.