The plural voting system refers to a voting system where eligible voters exercise only one vote, but some voters with specific qualifications have the ability to cast more than one vote. This means that not all voters have an equal say in the election process. Instead, certain individuals, such as high-ranking officials or those with certain qualifications, are granted the privilege to have multiple votes. This system is often criticized for being undemocratic as it can lead to unequal representation and favoritism towards certain groups. Therefore, correct answer is option 3, where eligible voters exercise one vote and some voters with specific qualifications cast more than one vote.