How many methods at least should be implemented in class C to prevent a compile error? public interface I1{ int i = 2; public int getVal(); } public interface I2 extends I1{ int j = 3; public int getVal2(); } public interface I3{ int i = 4; public int getVal(); } public abstract class AC implements I2{ int k = 5; public abstract void setVal(int k); public int getK(){ return k; } } public class C extends AC implements I3 { : : : }