Step 1: Read what the component must do.
We want the part of a browser that takes HTML, CSS and JavaScript and produces the visual page on screen.
Step 2: Recall the rendering engine's role.
The rendering engine parses HTML and CSS, builds the layout, and paints the pixels you see. Examples are Blink, Gecko and WebKit.
Step 3: Rule out the JavaScript engine.
The JavaScript engine only runs script code; it does not lay out or paint the page by itself.
Step 4: Rule out TLS.
Transport Layer Security just encrypts the connection; it has nothing to do with drawing.
Step 5: Rule out the network protocol stack.
The network stack moves bytes between machines but does not build the visible page.
Step 6: Conclude.
The component that turns code into the page you interact with is the rendering engine.
\[ \boxed{\text{Rendering Engine}} \]