Hello Student,

If you find that an answer mentioned in the answer key is incorrect then you should definitely challenge it. This can be done using the response sheet issued by the authorities. The response sheet is issued solely for the purposes of identifying any incorrect answers and hance the opportunity should be utilised. 

Even if you turn out to be wrong there is nothing to be feared as no steps would be taken towards your results because of it.

Hope this helps.

All the best!