Fixed: #3354 (#5038)

* Fixed variable names in Q9 for OOP quiz

* Fixed dictation and correct answer of Q34 of OOP

Inside the body of a static constructor, only static members of a class are accessible.

* Fixed Q35 of OOP quiz dictation

* Update object-oriented-programming-quiz.md

* Update object-oriented-programming-quiz.md

* Updated Q62 of OOP quiz

The choices are a copy of Q61 and are thoroughly irrelevant to Q62

* Fixed dictation of a choice in Q65 of OOP quiz

* Added two new questions (Q66, Q67) for OOP Quiz

* Added reference for Q66 of OOP quiz

* Fixed: #3354

Unchecked the current answer and added proper explanation.

* #3354

Added back official documentations link

c-sharp/c-sharp-quiz.md

@@ -718,12 +718,13 @@ public int Password
 
 #### Q67. How would you access the last two people in an array named People?
 
-- [x] `People[..^2]`
+- [ ] `People[..^2]`
 - [ ] `You cannot do this in C#.`
 - [ ] `People[..^3]`
 - [ ] `People[^2]`
 
-[Official Documentation: Ranges](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/ranges)
+Explain: You **can** do this in C#. However, none of the above answers are correct. You could access the last two items by using `People[^2..]`. Please see [issue #3354](https://github.com/Ebazhanov/linkedin-skill-assessments-quizzes/issues/3354) for more information.
+See also: [Official Documentation: Ranges](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/ranges)
 
 #### Q68. When can anonymous types be created?