Removing master page template entries

Is there a way of removing unwanted master page template entries that show in the "Master page" drop-down so that my client is not confused about which one to choose?

Screenshot here to explain:

https://www.dropbox.com/s/lxq26a2ogjepcfl/Screen%20Shot%202015-11-11%20at%2010.08.11.png?dl=0