What kind of primary does the following scenario describe?

A candidate competes in a state’s presidential primary and wins 26 percent of the popular vote.
Twenty­six percent of the state’s delegates are officially pledged to vote for that candidate at
the national party convention.

primary with winner­take all rules
primary with proportional*** representation rules
preference primary
open primary

Yep!

primary with proportional*** representation rules is the correct ans.

The kind of primary that the scenario describes is a primary with proportional representation rules.

To arrive at this conclusion, we look at the key details in the scenario. The fact that the candidate wins 26 percent of the popular vote suggests that the delegates are allocated based on the proportion of votes received by each candidate, as opposed to a winner-take-all system where all delegates would be awarded to the candidate with the most votes.

Furthermore, the fact that 26 percent of the state's delegates are officially pledged to vote for that candidate at the national party convention indicates that the delegates are allocated proportionally based on the popular vote. In other words, the number of delegates pledged to each candidate reflects the percentage of votes that each candidate received.

Therefore, the scenario describes a primary with proportional representation rules.