* document.cookie retrieves the cookie string.
* Setting document.cookie = ' key=John Smith ' adds or updates only that one cookie.
Important details:
* Writing to document.cookie does not overwrite all cookies .
* The browser does not require URL encoding , though it is recommended. Non-encoded spaces are allowed and automatically handled.
* document.cookies does not exist; the correct property is document.cookie.
Therefore, the correct behavior:
* Cookies are read.
* A new cookie key=John Smith is set.
* Existing cookies remain.
JavaScript Knowledge References (text-only)
* Writing document.cookie appends or updates cookies, not replaces them.
* document.cookie is both getter and setter for cookie strings.

Facts about JavaScript Promises:
* runParallel() is declared async, which means it always returns a Promise .
* Promises are consumed using .then(), .catch(), and .finally().
* There is no .done() method in native JavaScript Promises.
* The async keyword cannot be placed before a function call (option A is invalid syntax).
Analysis of each option:
A). async runParallel().then(data);
Invalid syntax. async cannot prefix an expression.
B). Valid. Calls the function and attaches a .then() handler.
C). Invalid. .done() is not part of JavaScript Promise API.
D). Valid. Calls runParallel() and chains .then().
Therefore the correct answers are B and D.
JavaScript Knowledge References (text-only)
* async functions return Promises.
* Promises use .then() to retrieve resolved values.
* .done() is not part of the standard Promise interface.

Initial array:
[1, 2, 3, 4, 4, 5, 4, 4]
The loop removes every value equal to 4:
* array.splice(i, 1) removes the element at index i and shifts all later elements left.
* i-- ensures the next index is checked correctly after the shift, preventing skipping elements.
Step-by-step removal:
* Remove the first 4 # array becomes [1,2,3,4,5,4,4]
* Remove next 4 # [1,2,3,5,4,4]
* Remove next 4 # [1,2,3,5,4]
* Remove last 4 # [1,2,3,5]
Final result:
[1,2,3,5]
Option B is correct.
JavaScript Knowledge References (text-only)
* splice(index, deleteCount) removes elements and shifts remaining items.
* Adjusting the loop index when deleting prevents skipping items.
* Arrays update length dynamically after splice().

Node.js event-based modules use the EventEmitter pattern.
The correct syntax for listening to events is:
emitter.on( ' eventName ' , callback)
The server library emits an ' error ' event, which must be listened to using .on.
Option analysis:
* A: .catch is for Promises, not EventEmitters.
* B: .error is not an EventEmitter method.
* C: Correct. Listens to the ' error ' event.
* D: try...catch only captures synchronous errors, not event-based asynchronous errors.
Therefore, the correct answer is option C .
JavaScript Knowledge References (text-only)
* The EventEmitter API uses on(event, handler) to listen for events.
* Errors emitted asynchronously cannot be caught with try...catch.
* The ' error ' event is standard for Node.js modules to signal operational errors.

We have a ternary:
account.style.display = accountName.includes(parsedSearchString)
? /* if true */
/* if false */;
Requirement:
* If the account matches the search string # show it.
* If it does not match # hide it.
For display:
* Show: ' block ' (or similar visible value).
* Hide: ' none ' .
So we want:
account.style.display = accountName.includes(parsedSearchString)
? ' block '
' none ' ;
That corresponds to option A.
Why others are wrong:
* B, C use values suitable for visibility, not display.
* D ( ' none ' : ' block ' ) inverts the logic, hiding matches and showing non-matches.