The product of all possible values of \( \alpha \), for which \( \displaystyle \lim_{x \to 0}\left(\dfrac{1 - \cos(\alpha x)\cos((\alpha + 1)x)\cos((\alpha + 2)x)}{\sin^{2}((\alpha + 1)x)}\right) = 2 \), is:
\( -2 \)
\( 1 \)
\( -1 \)
\( \dfrac{5}{4} \)