[sf56]

Hi Guys,
While trying to install standalone Ubuntu I reached a point where the system ask me to choose one of the following options:
The computer currently has multiple OS on it. what would you like to do?
1) Erase disk and install Ubuntu
2) Encrypt the new Ubuntu ....
3) Use LVM with the new Ubuntu .....

something else
you can create or resize partitions ....

so, which one should I use assuming I would like to be able to recover chromeOS?

Thanks
SF