Let \( \alpha \) and \( \beta \) be the roots of the equation \( x^2 + (2i - 1) = 0 \) Then, the value of \( \lvert \alpha^8 + \beta^8 \rvert \) is equal to:
\( 50 \)
\( 250 \)
\( 1250 \)
\( 1500 \)