answer with explains and reasons please ( ill mark brainlist )

Mount Everest is the world's highest mountain. It is 29,028 feet (9km) above sea level. It is located in the Himalayas between Nepal and China. But now that we have sonar, we know about Mauna Kea. Mauna Kea is on Hawaii Island. It is 13,448 feet (4km) above sea level. From its base on the ocean floor, it is 33,796 feet (10km)! Should we still consider Mount Everest to be the highest mountain? Why or why not?