What will the altimeter indicate if the static source gets blocked at 2300 feet and the airplane continues a straight and level flight?

When the static source gets blocked, the altimeter freezes at the altitude where the blockage occurred because it cannot sense pressure changes. Since the aircraft continues straight and level at the same altitude, the altimeter will correctly indicate 2300 feet (the altitude at the moment of blockage). The static port is essential for the altimeter to function.