How to enable & disable this option?

Question

How to enable and disable this option only, not the whole object with C# ?

Answer 1

If I understand correctly you're trying to achieve is to disable just a component and not the whole gameobject.

You can get any component (on the current object) using

var component = GetComponent<Type>();

Where Type is the component you want to get. Examples in your case:

var camera = GetComponent<Camera>();
var canvas = GetComponent<Canvas>();

Here GetComponent is called on the current gameObject where your script is, but you can call it on another gameObject, it's a public function.

Then all components can be enabled/disabled:

component.enabled = false; // Disable
component.enabled = true; // Enable

// Examples
camera.enabled = true; 
canvas.enabled = false; 

Finally, notice that the checkbox only appears in the inspector next to a component if some methods are found by Unity (usually: Start and Update).