要分析该代码的输出结果，我们需要逐步跟踪变量的变化情况。我们假设代码缩进是正确的。以下是经过正确缩进和分析后的代码：

```python
a = 1
b = 2
for i in range(0, 2): # i will take values 0 and 1
a += i
for j in range(4, 6): # j will take values 4 and 5
b += i
print(a + b)
```

### 分析步骤：

1. **初始值**:
- \( a = 1 \)
- \( b = 2 \)

2. **第一轮外层循环** (\( i = 0 \)):
- \( a = a + i = 1 + 0 = 1 \)
- 内层循环:
- \( j = 4 \),
\( b = b + i = 2 + 0 = 2 \)
输出: \( a + b = 1 + 2 = 3 \)
- \( j = 5 \),
\( b = b + i = 2 + 0 = 2 \)
输出: \( a + b = 1 + 2 = 3 \)

3. **第二轮外层循环** (\( i = 1 \)):
- \( a = a + i = 1 + 1 = 2 \)
- 内层循环:
- \( j = 4 \),
\( b = b + i = 2 + 1 = 3 \)
输出: \( a + b = 2 + 3 = 5 \)
- \( j = 5 \),
\( b = b + i = 3 + 1 = 4 \)
输出: \( a + b = 2 + 4 = 6 \)

### 输出总结：
- 输出顺序为：3, 3, 5, 6

**正确答案是：C: 6**

因此，代码的最终输出值是 6。