1TB external HDD for time machine backup... what format?

[V8burble]

I've got a WD 1TB drive that I want to use to make a huge Timemachine backup of my iMac before it goes in to have a new hard disk fitted tomorrow. So I thought I'd just erase all the 'stuff' that is on it before I started the backup going overnight but when I look on the Mac disk utility it gives me a few format options when it erases the drive:

Mac OS Extended (journaled)
Mac OS Extended (case sensitive, journaled)
MS-DOS (FAT)
ExFAT

Anyone know which I should specify? I'm lost with this sort of thing :bonk:

 

[V8burble]

Aaah, having just read Time machine support pages it looks like Mac OS Extended (journaled is the way to go.