Which of the following is not a method of election?

The option that is not a method of election is "Single-member constituency." Single-member constituency is not a method of election, but rather a type of electoral district. It refers to a constituency or district that elects only one representative to a legislative body, such as a parliament or congress. The other options are all methods of election. - Simple majority is a method of election where the candidate with the most votes is elected, even if they do not receive an absolute majority (more than 50%) of the votes. - Proportional representation is a method of election where seats in a legislative body are allocated proportionally to the number of votes received by each political party or group. - Plurality system is a method of election where the candidate with the most votes in a single-member constituency is elected, regardless of whether they receive an absolute majority or not. - Absolute majority is a method of election where the candidate must receive more than 50% of the votes to be elected. If no candidate receives an absolute majority, a run-off election may be held.