Can an LLC be a Holding Company for Subsidiary corporations?

[Anthony Ezimoha]

Hello all

I am a Real Estate Agent and studying for my Mortgage Broker license. I plan to create multiple service business related to Real Estate as c- corporations 

I would like to form a Holding Company as the parent company over the businesses. Should the Holding company be LLC's or C-Corps?

Advantages or Disadvantages of either?