Answer:
The statement that is the correct interpretation of Sebastian’s words in the excerpt is "Sebastian feels he may be suffering from amnesia after the shipwreck, and refers to the river Lethe, which is associated with forgetfulness in Greek mythology"
Step-by-step explanation:
This excerpt from act IV, scene I, of Twelfth Night, show the bewilderment of Sebastian and even the words he uses and the way he expresses them seem to make no sense, everything is unreal for him in this lines so he fears to be dreaming or losing his mind in a new reality without memories, as he refers to the river Lethe.