Here's an example to tell why you should read all options even when you think you reached the answer
5 year old child with repeated bacterial and fungal infections and negative nitrozolium blue test.
What intracellular mechanism is missing?
a- defensin
b- hydrogen peroxide
c- myeloperoxidase
d- hypochlorite
e- NADPH oxidase
Am sure that when you reach hydrogen peroxide you'll pick it and leave the question happily, but if you'd have continued reading the options carefully the NADPH oxidase option would have changed your mind.