Step 1: Identify the core action and subject. Part R, "a cultural event," and Part Q, "was held by," together form the core of the sentence, with "a cultural event" as the subject and "was held by" as the verb phrase. So, RQ ("a cultural event was held by") starts the sentence.
Step 2: Determine who held the event. Part P, "school students," logically follows as the group that held the event, making RQP ("a cultural event was held by school students").
Step 3: Add the location or context. Part S, "at the Meet," specifies where the event took place, fitting at the end. Thus, RQPS ("a cultural event was held by school students at the Meet") forms a coherent sentence, which matches option C.