2. Around a table are sitting 4 people, each of whom can either be a knight (who always tells the truth) or a knave (who always lies). Each of those present states: "Of the other three people sitting at this table with me, the knaves are exactly two." What is the total number of knaves sitting at the table?
(A) none
(B) 
definitely 2
(C) definitely all 4
(D) definitely 1
(E) the information provided is not sufficient to determine it
(2) The correct answer is $(E)$.

If at the table there are two scoundrels and two knights, each knight actually tells the truth, because they see two scoundrels, and each scoundrel actually lies, because they see only one scoundrel. Similarly, if at the table there are only scoundrels, each sees three scoundrels, and thus actually lies. The provided elements therefore do not allow concluding whether there are two or four scoundrels at the table.

Problem proposed by Matteo Protopapa.