In a fish population in a shallow stream, the genotypic frequencies of yellowish-brown fish and greenish-brown fish changed significantly after a flash flood randomly swept away individuals from that...

In a fish population in a shallow stream, the genotypic frequencies of yellowish-brown fish and greenish-brown fish changed significantly after a flash flood randomly swept away individuals from that stream. This change in genotypic frequency was most likely attributable to:

a) gene flow. b) disruptive selection. c) directional selection. d) stabilizing selection. e) genetic drift.