In exponential smoothening method, which one of the following is true?

- $0 \leq \alpha \leq 1$ and high value of $\alpha$ is used for stable demand
- $0 \leq \alpha \leq 1$ and high value of $α$ is used for unstable demand
- $\alpha \geq 1$ and high value of $\alpha$ is used for stable demand
- $\alpha \geq 0$ and high value of $\alpha$ is used for unstable demand