Which of the following tools will you use to analyze variability trend of Featured snippet occurrence for the last 30 days?

Semrush Sensor is the correct tool because it monitors daily fluctuations in SERP features, including Featured Snippets, across various industries and countries. This allows you to track the variability trend of their occurrence over time, such as the last 30 days. Organic Research shows keyword rankings and SERP features for specific keywords but doesn't provide an aggregate variability trend across a broader set of keywords or an entire industry. Custom reports might offer this, but Sensor provides it readily. On Page SEO Checker focuses on on-page optimization factors and doesn't track SERP feature variability.