The problem can be reworded as
is $$ |x-y| - |x-z| > 0 $$
$$ |x-y| $$ implies the following
$$ x - y $$ when $$ x - y > 0 $$
or $$ x - y $$ when $$ x > y $$
$$ y - x $$ when $$ x - y < 0 $$
or $$ y - x $$ when $$ x <y> z $$
$$ z - x $$ when $$ x < z $$
$$ | y | - | z | <0> 0 $$
$$ -y $$ when $$ y <0> 0 $$
$$ -z $$ when $$ z < 0 $$
This is pretty useless because its impossible to tell what is what on a number line
B says
$$ x < 0 $$
This is pretty useless by itself as well
Lets combine the two
From A and B , if x < 0 the intervals that we are worried about are y , z , 0
Doing the maths on the intervals
<------y-------z-------- 0
---y-z ---y-z ---z-y (whoops this is positive while y-z is negative)
This implies that we can't tell whether |x-y| - |x-z| > 0 by using both statements. Hence I think the answer is E
Note that I did not check for boundary condition like when x = y , x=z and x = 0 since I could deduce E from just looking at the intervals alone
I would be interested to run this by someone else who's a veteran of this method. I have just read these notes yesterday ...