Answer: The king believes his son has drowned.
Step-by-step explanation:
Previously, we have learned, through Prospero and his familiar spirit Ariel’s conversation, that was Ariel who caused the tempest that struck the ship transporting Alonso, Ferdinand, Sebastian, Antonio, Gonzalo, Stephano, and Trinculo, Making sure they all got safely to the island but were segregated into small groups.
On another part of the island, Alonso, Sebastian, Antonio, Gonzalo, and other miscellaneous lords give thanks for their safety but worry about the fate of Ferdinand.
Alonso ends up in a group with Sebastian, Antonio, and Gonzalo, and are fearful that Ferdinand may have drowned. Alonso regrets marrying his daughter because it was the reason for them to make the sea journey in the first place.