* JSON.stringify(john) converts the john object into a JSON string.
* When you JSON.parse that string back, you get a plain object :
* Only data that can be represented in JSON is preserved (numbers, strings, booleans, arrays, plain objects).
* Functions are not preserved and are dropped.
* So dan is a plain object with properties firstName and lastName, but no name method .
* Therefore, dan.name is undefined, and dan.name() throws:
TypeError: dan.name is not a function
The literal string interpolation inside console.log( ' Hello ${...} ' ) is also wrong (single quotes), but the code never reaches that line.

The syntax:
import printPrice from ' module ' ;
means the module must export its function as a default export :
export default function printPrice() { ... }
Why the others are wrong:
* Named exports require curly braces:
* import { printPrice } from ' module ' ;
* "all export" and "multi export" are not JavaScript terms.
Therefore, printPrice must be the default export .
JavaScript Knowledge References (text-only)
* Default imports use: import name from ' module ' .
* Named imports require braces: import { name } from ' module ' .

Comprehensive and Detailed Explanation:
Assuming SaleItem inherits from Item via prototype (e.g. SaleItem.prototype = Object.create(Item.prototype)):
* Lines 01-02: create regItem and saleItem.
* Line 03: define Item.prototype.description.
Now both regItem and saleItem (via inheritance) have a description method from Item.prototype.
* Line 04: regItem.description() # ' This is a Scarf ' .
* Line 05: saleItem.description() # ' This is a Shirt ' (same method, but this.name is ' Shirt ' ).
* Line 07: SaleItem.prototype.description = ... overrides description only for SaleItem instances going forward.
If we imagine calling regItem.description() and saleItem.description() again after line 07:
* regItem.description() still uses Item.prototype.description # ' This is a Scarf ' .
* saleItem.description() now uses SaleItem.prototype.description # ' This is a discounted Shirt ' .
Those four lines correspond to option B.

The correct answers are C and D .
The statement:
const arr = Array(5).fill(0);
creates an array with 5 elements , and every element is filled with the value 0.
So the array becomes:
[0, 0, 0, 0, 0]
A professional test should verify both important expectations:
arr.length === 5
and:
each element === 0
Option C is correct because it checks every element in the array:
arr.forEach(e = > console.assert(e === 0));
This confirms that each array element was filled with 0.
Option D is correct because it checks the array length:
console.assert(arr.length === 5);
This confirms that the array contains exactly five elements.
Option A is incorrect because the array length is not 0; it is 5.
Option B is incorrect for two reasons. First, arr[5] is outside the valid index range. The valid indexes are:
0, 1, 2, 3, 4
So:
arr[5]
returns:
undefined
Second, arr.length === 0 is false because the length is 5.
Therefore, the verified answers are C and D .

The goal:
" Temporarily and quickly remove them. "
The fastest way is to run a script in the browser console that removes all such elements:
document.querySelectorAll( ' .ad-library-item ' ).forEach(el = > el.remove()); This immediately removes all 50+ elements and requires no page reload.
Option analysis:
* A & B : Preventing load events is unreliable and does not remove already-created DOM nodes.
* C : Correct-console code can remove all matching DOM elements instantly.
* D : Possible but extremely slow; removing 50+ elements one by one in the inspector is not "quick." Therefore, C is the best answer.
JavaScript Knowledge References (text-only)
* The browser console can run arbitrary JavaScript that manipulates the DOM.
* document.querySelectorAll() returns all matching DOM nodes.
* Nodes can be removed using .remove().