The sentence suggests that the farmers are protesting against the increasing prices. "Make themselves heard" indicates that they are trying to voice their concerns and make their issues known to others, which fits the context of a protest.
Option (A), show their virility, is incorrect as it doesn’t fit the context of protesting against prices. "Virility" refers to manliness or strength, which is irrelevant here.
Option (C), curb the prices, is a reasonable choice, but it implies an outcome rather than the action the farmers are taking. The farmers are staging a picket to protest, not necessarily to directly control the prices.
Option (D), topple the government, is a strong statement but doesn't quite align with the context of protesting price increases, which is more about raising awareness than taking extreme action.
Thus, option (B) is the best choice.