Which method in the code below is single level inherited?

Which method in the code below is single level inherited?

class A
{
 protected int a, b;
 public: void show()
 { 
  cout<<a<<b;
 }
};
class B: public A
{
 public: void disp()
 { 
  cout<<a++<<b++; 
 }
};
class C: private A, public B
{
 void avg()
 { 
  cout<<(a+b)/2; 
 }
};