Let \( \alpha, \beta \) be two roots of the equation \( x^{2} + (20)^{1/4}x + (5)^{1/2} = 0 \). Then \( \alpha^{8} + \beta^{8} \) is equal to:
\( 160 \)
\( 10 \)
\( 50 \)
\( 100 \)