int foo(int n)               //Line 1{                            //Line 2  if (n == 0)                //Line 3     return 0;               //Line 4  else                       //Line 5     return n + foo(n - 1);  //Line 6}                            //Line 7
Consider the accompanying definition of a recursive function. Which of the statements represents the base case?

A. Statements in Lines 1-6.
B. Statements in Lines 3 and 4.
C. Statements in Lines 5 and 6.
D. Statements in Lines 3, 4, and 5.

Answer: B