Is a dvd meant to be mode 1 or mode 2.

I thought it was mode but in prassi when i load a dvd image, then click Recording Options, there are 3 options there.

CD Mode 1 (Blocking 2048) - DVD
CD Mode 2 XA (Blocking 2336) - DDCD
CD Mode 2 XA (Blocking 2352)

I assume i use CD Mode 1 - DVD.

Also, do i need to check the box that says

Check for Post-Gap and Add the 150 zeroed blocks if needed.

cheers