Chapter 2.2A, Problem 6A

Which of the following represent equal sets?

$A=\left\{a,b,c,d\right\}$

$B=\left\{x,y,z,w\right\}$

$C=\left\{c,d,a,b\right\}$

$D=\left\{x|1\le x\le 4\text{ and }x\in N\right\}$

$E=\varphi$

$F=\left\{\varphi \right\}$

$G=\left\{0\right\}$

$H=\left\{\right\}$

$I=\left\{x|x=2n+1\text{ and }n\in W\right\}$

$L=\left\{x|x=2n-1\text{ and }n\in N\right\}$