[tex]\huge\boxed{\text{Dominic}}[/tex]
In this problem, [tex]0[/tex] represents the sea level. Since Dominic is [tex]175[/tex] feet below the surface (sea level), his current location is at [tex]-175[/tex] feet.
The same concept can be applied to Karen, who is at [tex]-138[/tex] feet.
We need to find who is lower, or farther below [tex]0[/tex]. This means the answer is [tex]\boxed{\text{Dominic}}[/tex].
