Answer: 1.Sebastian meets Feste, who mistakes him for Viola/Cesario.
2. Olivia mistakenly thinks Sebastian is Cesario.
3.Feste, disguised as Sir Topas, ridicules Malvolio in the dark cell.
4.Sebastian thinks that he is suffering from memory loss or has gone mad.
5.Olivia gets a priest and marries Sebastian, still thinking he is Cesario.
Explanation:
The correct answer is D, this is 'present perfect' tense. It is formed with the use of the verb HAVE in present simple tense (so, HAVE/HAS), and the past participle of a verb (or the third column of irregular verbs).
A cannot be correct, because then it would say - I hear.
B cannot be correct, because then it would say - I had heard.
C cannot be correct, because then it would say - I heard.
And since there is also HAVE HEARD, the correct answer has to be D.