Question 15 1 pts Given classes: public class Building public class House extends Building then Building b = new House ; is an example of upcasting encapsulation downcasting Question 16 1 pts Abstract Classes have only abstract methods True False Question 17 1 pts Abstract classes can be used as types in method signatures o True False Question 18 1 pts The binary search algorithm has complexity o On^2) Odlog n) O(n) On log n)