Choice C is the best answer. The passage states that "when Lymie put down his fork and began to count . . . the waitress, whose name was Irma, thought he was through eating and tried to take his plate away"(lines 34-38,"Austrian...his"). It is reasonable to assume that Irma thinks Lymie is finished eating because he is no longer holding his fork.
Choice A is incorrect because Lymie has already been reading his book while eating for some time before Irma thinks he is finished eating. Choice B is incorrect because the passage doesn't state that Lymie's plate is empty, and the fact that Lymie stops Irma from taking his plate suggests that it is not empty. Choice D is incorrect because the passage gives no indication that Lymie asks Irma to clear the table.