Final answer:
To track conversions on a Marketo landing page, the Landing Page Performance report is the most relevant. It offers detailed analytics including the number of people who have completed a desired action on the landing page.
Step-by-step explanation:
If you want to figure out how many people converted on a Marketo landing page, you would use the B. Landing Page Performance report. This report provides detailed analytics on how each landing page is performing in terms of page views, unique visitors, and most importantly conversions.
These conversions indicate the number of people who have completed the desired action, such as filling out a form on the page. While other reports like Web Page Activity, Program Performance, and Lead Performance can offer insights into overall visitor behavior, lead acquisition and program success respectively, it's the Landing Page Performance report that specifically tracks conversion metrics associated with individual landing pages within Marketo.