This is bullshit! Whether it is strict or not has nothing to do with this. The difference between them is that:

Option a means that if 0

Option c indicates that if 0; 0, and there is no limit to the relationship between two function values.

Note: The question does not give any hint as to whether f'(x) is continuous at 0, so there is not necessarily an area where the derivative sign is unchanged, so A is not strict enough.