Which among the following best defines abstraction? Hiding the implementation Showing the important data Hiding the important data Hiding the implementation and showing only the features In which of the following cases dynamic arrays are not preferred? a) If the size of the array is unknown b) If the size of the array changes after few iterations c) If the size of the array is known d) If the array holds a variable number of elements If the size of the array is unknown If the size of the array changes after few iterations If the array holds a variable number of elements If the size of the array is known