What would the browser output if the following script is executed?

```
< SCRIPT LANGUAGE = "JavaScript" >
var array = [ [ 1, 2, 3 ], [ 1, 2, 3 ] ];
for ( var i in array ) {
for ( var j in array[ i ] )
document.write( array[ i ][ j ] + " " );

document.writeln("
");
}
< /SCRIPT >
```

a) Nothing, the script would generate an error
b) 1 2 3
c) 1 2 3 4 5 6
d) 1 2 3 1 2 3

d) 1 2 3 1 2 3