The most likely answer choice should and would be B, given that rabbits are herbivores (meaning that they only eat vegetation and plants, including grass). Buffalo's food source(s) and diet consists of grass as well. If enough rabbits are introduced into a grassland area, they will furthermore consume more grass, in turn limiting the food source of the buffalo.
''Attacking'' prey doesn't necessarily make sense, given that buffalos do not 'prey' on any animal and rabbits themselves are prey.
A to a lesser extent can make sense, although I doubtable. B's most likely the answer.
If i remember correctly asexual reproduction came first because without asexual reproduction the cells would not have been able to produce other cells so what few cells there were reproduced asexually and then it evolved onto sexual reproduction later in development
