What should the in-text citation read for the following?

The main character Billy Pilgrim observes that time is moving abnormally in response to the clock's twitching hands.

Source: Slaughterhouse-Five by Kurt Vonnegut, chapter 1, page 20. Published by Dell Publishing, New York 1991:

Original Text:
The time would not pass. Somebody was playing with the clocks, and not only with the electric clocks, but the wind up kind too. The second hand on my watch would twitch once, and then a year would pass, and then it would twitch again.

Group of answer choices

The main character Billy Pilgrim observes that time is moving abnormally in response to the clock's twitching hands. (Vonnegut 20)

The main character Billy Pilgrim observes that time is moving abnormally in response to the clock's twitching hands (Slaughterhouse-Five, 20).

The main character Billy Pilgrim observes that time is moving abnormally in response to the clock's twitching hands (Slaughterhouse-Five, Vonnegut).

The main character Billy Pilgrim observes that time is moving abnormally in response to the clock's twitching hands (Vonnegut 20).