For a puzzlers’ party in 1993, University of Wisconsin mathematician Jim Propp devised a “self-referential aptitude test,” a multiple-choice test in which each question except the last refers to the test itself:

1. The first question whose answer is B is question

(A) 1

(B) 2

(C) 3

(D) 4

(E) 5

2. The only two consecutive questions with identical answers are questions

(A) 6 and 7

(B) 7 and 8

(C) 8 and 9

(D) 9 and 10

(E) 10 and 11

3. The number of questions with the answer E is

(A) 0

(B) 1

(C) 2

(D) 3

(E) 4

The full 20-question test is here, the solution is here, and an interesting collection of solving routes is here.

(Jim Propp, “Self-Referential Aptitude Test,” *Math Horizons* 12:3 [February 2005], 35.)