[Grammar] This is the place that I was born / born in

[wotcha22]

Please check out which sentences are correct.

1. This is the place where I was born.
2. This is where I was born.
3. This is the place that I was born.
4. This is the place that I was born in.
5. This is the place which I was born in.
6. This is the place in which I was born,

I know 1,2,5,and 6 are absolutely grammatical.

I wonder which one is grammatical between 3 and 4.

Thank you.

 

[Rover_KE]

4 is OK.