Which of the following is true about pure virtual functions?
1) Their implementation is not provided in a class where they are declared.
2) If a class has a pure virtual function, then the class becomes abstract class and an instance of this class cannot be created.
(A) Both 1 and 2
(B) Only 1
(C) Only 2
(D) Neither 1 nor 2
Explanation: See http://en.wikipedia.org/wiki/Virtual_function#Abstract_classes_and_pure_virtual_functions
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