Identifying Proportional Representation

In the context of United States elections, various electoral systems are used to determine how votes are translated into seats won by candidates in legislative bodies. One of the most commonly used systems is the plurality voting system, also known as 'winner-takes-all.' In this system, the candidate who receives the most votes in a district wins. Understanding different electoral systems is crucial for analyzing how they impact voter representation and party dynamics.

Which of the following electoral systems awards seats to candidates in proportion to the number of votes they receive?