Why is a sentence with a nested structure more difficult for readers to understand, compared to a sentence without a nested structure?

a. Nested structures require the passive voice; readers need to switch around the subject and the object of the sentence.
b. Sentences with nested structures typically include many negative words (such as not and deny). Therefore, readers need to translate the sentence into a linguistically positive sentence.
c. Sentences with a nested structure require readers to store the first part of the sentence until they have processed later parts of the sentence.
d. In a sentence with a nested structure, the deep structure and the surface structure are fairly similar to one another, creating an ambiguity that is difficult to resolve.

Ans: c