Alleged madness
The passage from Act 3 Scene 4 has the recurring idea of alleged madness. First, Olivia, Maria, Sir Toby and Fabian were all making Malvolio seem crazy and devil-possessed with his snobbery and arrogance. Then, the passage shows Olivia desperately in love, thinking she is like Malvolio--going mad. Lastly, Antonio's friendship to Sebastian ( who was actually Cesario) was introduced. Antonio was made to seem mad from his misdirected loyalty.
True because figurative language is used to pack multiple possible meanings in a stanza or few words
b. garden
A preposition is found in a sentence in which it introduces information to the reader like a location perhaps. The object of the preposition can be a noun, a pronoun or even a gerund that is usually together with the preposition in order to complete a prepositional phrase. In the statement above, the prepositional phrase is "on the garden", therefore the preposition is "on" and the object of the preposition is the "garden" to which the preposition "on" refers to.