$\"\"$

The expression is $\"\"$ .

$\"\"$ (Substitute $\"\"$ for x and $\"\"$ for y)

$\"\"$ (The absolute value of 12 is 12)

Both have different signs, so subtract the lesser absolute value from greater absolute value.

$\"\"$ (Different signs: Subtract $\"\"$ from $\"\"$ )

$\"\"$ ( $\"\"$ > $\"\"$ , so the sum has the sign as $\"\"$ )

The expression is $\"\"$ . $\"\"$

The answer is C.