A developer needs to render a Page Designer page in JSON format.

The correct syntax to render a Page Designer page in JSON format in Salesforce B2C Commerce is Option C: PageMgr.renderPage(pageID, {parameter1: value1}). This syntax correctly invokes the renderPage method from the PageMgr class, which is used to render pages constructed with the Page Designer tool. The method accepts the page ID and an object representing additional parameters, allowing the developer to specify how the page should be rendered, including format specifications like JSON.