Final answer:
A second-round election where the top two candidates from the first round compete is known as a runoff election, ensuring the winner has majority support.
The correct option is 2.
Step-by-step explanation:
The "second-round" election in which voters choose between the top two candidates from the first round is called a runoff election.
This situation typically arises when no candidate wins an outright majority, which is defined as 50 percent plus one vote, in the initial election. Runoff elections ensure that the eventual winner has the support of the majority of the voters and are commonly used in non-partisan races and in states with majority vote requirements for statewide offices.
The correct option is 2.