Browse Questions
Home  >>  AIMS  >>  Class11  >>  Math  >>  Sets

# Which of the following is not a singleton set?  (A) { x : |x| = 5, x $\in$ N } (B) { x : |x| = 6, x $\in$ Z }  (C) { x : $x^2$ + 2x + 1 = 0, x $\in$ N } (D) { x : $x^2$ = 7, x $\in$ N }

B,C and D
Hence (C) is the correct answer.