What is the output of the following code?

```
public class Test {
public static void main(String[] args) {
int[][] matrix =
{{1, 2, 3, 4},
{4, 5, 6, 7},
{8, 9, 10, 11},
{12, 13, 14, 15}};

for (int i = 0; i < 4; i++)
System.out.print(matrix[i][1] + " ");
}
}
```
a. 1 2 3 4
b. 4 5 6 7
c. 1 3 8 12
d. 2 5 9 13
e. 3 6 10 14

d. 2 5 9 13