Answer: option B.
Step-by-step explanation: If the altimeter is calibrated with respect to the sea level, this device will show the number of feet that the user is with respect to the sea level, where if the user is at the sea level, the altimeter will show +0 ft, if the user is above the sea level the altimeter will show a positive number, and if the user is bellow the sea level, the altimeter will show a negative number (this may depend on the altimeter you are using)
We know that Raul is located 320 feet above the sea level, so the altimeter will show +320 ft