Explanation:

Key Requirement:
Render a Page Designer page in JSON format (e.g., for headless commerce or API responses).

Why Option C?
✅ Correct Syntax for PageMgr.renderPage
The PageMgr.renderPage() method is used to render Page Designer pages programmatically.
To output in JSON, set the renderMode parameter to json:

PageMgr.renderPage(pageID, {
renderMode: 'json',
parameter1: value1 // Additional parameters if needed });

How It Works:
Returns the page structure (regions, components, and data) as JSON.
Used in controllers or scripts to integrate with headless frontends.

Why Not Other Options?
❌ A. PageMgr.serializePage()
Does not exist in the B2C Commerce API.

❌ B. JSON.stringify(PageMgr.renderPage())
Incorrect: renderPage() already returns JSON when renderMode: 'json' is set. Wrapping it in JSON.stringify is redundant.

Reference:
Salesforce Docs:
PageMgr.renderPage()
Page Designer JSON Output