Let the system of linear equations \( x + 2y + z = 2 \), \( \alpha x + 3y - z = \alpha \), \( -\alpha x + y + 2z = -\alpha \) be inconsistent. Then \( \alpha \) is equal to:
\( \frac{5}{2} \)
\( -\frac{5}{2} \)
\( \frac{7}{2} \)
\( -\frac{7}{2} \)