Which schedule? E or C?

I am a Realtor and I own rental properties. I advertise both my rentals and my real estate services using flyers, business cards, etc. typically with office depot or somewhere like that. Also I show client houses in the same areas where I have my rentals. While in town, I drop by the rental properties to check up on them.

 

Where do I write off the advertising and mileage? Schedule E (landlord/rentals) or Schedule C (real estate)?

 

A CPA told me that schedule E is passive and that you pay FICA on schedule C earnings so it’s best to reduce the adjusted income on schedule C.  I don't understand all that so can someone explain it in a bit more detail?