Hi there! The IR info for this compound tells us that this compound contains a carbonyl so we can easily eliminate choices c and d which contain -OH group that can be seen at around 3550-3200 cm-1. Compound A seems doesn't seem to have a symmetry and will show more than 4 signals due to the orientation of the protons in each C in the ring. Also, it appears that we don't have a singlet in compound A. B is the correct answer where the singlet with 3Hs are the protons in the right side of the ketone. You can use any of the info in the proton NMR to answer this problem
Hope that makes sense!