Some:
land reform and redistribution
There are three types of magma: basaltic, andesitic and rhyolitic magma. Basaltic magma have a characteristic runny liquid magma which contains low silica content. Andesitic magma is the intermediate one in terms of silica content and viscosity. The rhyolitic magma is the thick, high silica content magma.
A. Dam
All of the others are naturally formed, whereas a dam is manmade
(unless it's a beaver dam of course)
Genetic engineering is breaking the natural boundaries that exist between species and hybridization is pollinating a flower with pollen from a different species of flower.
Therefore, the answer is B.