To answer this question, consider what irony means; in its most common usage, irony is stating something that is different (often opposite) of the literal words used in the statement. It's ironic, for example, if a very large person has the last name "Small." Another sense of irony is a statement that expresses incongruity between the true result of something and the result that would normally be expected. It's ironic, for instance, that the Titanic was advertised as an "unsinkable" ship and it then sunk on its very first voyage.

None of the choices in the quoted passage seems ironic as one first reads "The Lottery." The correct answer becomes ironic only after the reader has finished the story and knows the outcome. In this sense, choice B expresses irony, because Tessie "wins" the lottery, and, in the end, the town does have to "get on" without her.

In "The Lottery" by Shirley Jackson, the line which contains irony is B, "Thought we were going to have to get on without you, Tessie" (Jackson 2). First of all, this is ironic because Tessie is the "winner" of the lottery, so she is necessary to the tradition. Secondly, since she is stoned to death to fulfill her lottery obligation, the town really will have to "get along without her" for the rest of their lives. Her children will have to get on without her because they will no longer have a mother. Her husband will have to get on without her because he will no longer have a wife. Her friends and her community will no longer have her as part of their neighborhood. Tessie is late to the lottery, and maybe had she known her name would be drawn this particular year, she might have chosen to not show up at all!