Which of the Following Statements Provides the Best Definition or Description

Which of the following statements provides the best definition or description for "the curtain principle"?

A) A subsequent mortgagee will lose its security if a prior mortgagee forecloses.
B) The sale of a residential property usually includes anything attached to the house,such as curtain rods and dishwashers.
C) An interest in land may be obtained through adverse possession if the owner does not use a "window of opportunity" to enforce its rights.
D) A purchaser of land should conduct a title search to ensure that there are no hidden interests in the property.
E) There is no need to look behind a certificate of title in order to identify valid interests in land.