Which of the following factors could have contributed to his AOM?

Which of the following factors could have contributed to his AOM?

A 4-year-old boy has had otitis media with effusion (OME) for several weeks and his condition has recently progressed to acute otitis media (AOM). Which of the following factors could have contributed to his AOM?Reflux of fluid from the boy’s nose into his middle earA deficiency in immunoglobulin GAccumulation of cerumen in the external acoustic meatusSensorineural deficits in the auditory control apparatusExposure to respiratory syncytial virus (RSV)