In a geometric progression consisting of positive terms, each term equals the sum of the next two terms. Then the common ratio of this progression equals :

Question

( A ) $\sqrt{5}$
( B ) $\frac{1}{2} (\sqrt{5} - 1)$
( C ) $\frac{1}{2} \sqrt{5}$
( D ) $\frac{1}{2} (1 - \sqrt{5} )$