If $S$ is the set of distinct values of $b$ for which the following system of linear equations
$$\begin{aligned} & x + y + z = 1 \\ & x + ay + z = 1 \\ & ax + by + z = 0 \end{aligned}$$
has no solution, then $S$ is:\\
(1) An empty set\\
(2) An infinite set\\
(3) A finite set containing two or more elements\\
(4) A singleton