Answer: Option(b) is correct
Explanation:
Gerrymandering is the practice of manipulation or alteration done in political district boundaries for favoring a particular advantage to a party. It is an unjust way of providing advantage so that it can harm other party's votes and effort by wasting it .
Other options are incorrect because prevention of legislation,limiting of bill in Senate and providing extra electoral benefit to major party are not described as gerrymandering .Thus, the correct opinion is option(b)