When a derived class has two or more base classes, the situation is knows as :
a.
multiple inheritance
b.
polymorphism
c.
encapsulation
d.
access specification

Explanation:

When a derived class has two or more base classes, the situation is knows as multiple inheritance.  

The above is almost the definition of multiple inheritance.  (Note: Java does not support multiple inheritance. )

Polymorphism is when an object can be expressed in different ways.

Encapsulation is when a programming method or style where some or all the related methods of an object class are contained within the the class.

Access specification appears to be a general expression that has multiple meaning, e.g. does access mean the database package Access, or used in a general sense?

(because i need 20 chars)

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