Which of the following groups contains more equations?  Group 1: $y=1$ $\quad$ $x+1$  Group 2: $c + 1 = b$ $\quad$~ $c \textless{} 2$  Group 3: $z = x$ $\quad$~ $z = 1$ 
选项为:A:Group 1  B:Group 2  C:Group 3  D:They all contain the same number of equations.  请回答其中一个选项.