Consider the following MATLAB command line evaluations:

$>a=[1$;$2e-8]$

$>b=[1e-16$;$0]$;

$>$norm$(a-b)-(norm(a)-$norm$(b))$

ans $=$

$,-2\mathrm{.}2204e-16$

The sign of the returned answer is mathematically incorrect.

The sign of the returned answer is mathematically correct but the magnitude is incorrect.

Both the sign and magnitude of the returned answer are mathematically correct.