these expressions could replace a call to this function?

Question

Consider the recursive function,
```
int rec(int n)
{
if (1 ==n )
return 1;
else
return rec(n-1) + 2*n - 1;
}
```

a) n 2 - 1
b) n 2 + 1
c) n 2
d) (n + 1) 2
e) (n - 1) 2

Answer 1

c) n 2