Here is the completely updated `question.php`. I added the missing `$breadcrumbs` array and defined `$category_name` and `$topic_name` right before the header is included. This ensures that `header.php` generates the correct Breadcrumb Schema, page title, and meta description for single question pages. Replace your entire `question.php` with this: ```php Data Structures & Algorithms Questions
Q. Which data structure follows the First-In-First-Out (FIFO) principle?
Queue
Linked List
Stack
Array

Explanation:

A queue is a linear data structure that follows the FIFO principle, where the element inserted first is the one to be removed first. A stack, on the other hand, follows LIFO (Last-In-First-Out).

Q. What is the primary purpose of an operating system?
To compile source code into machine code
To connect to the internet
To provide a graphical user interface
To manage hardware and software resources

Explanation:

An operating system manages computer hardware and software resources and provides common services for computer programs. It acts as an intermediary between the user and the hardware.

Q. Which protocol is used for secure communication over a computer network?
SMTP
FTP
HTTPS
HTTP

Explanation:

HTTPS (Hypertext Transfer Protocol Secure) is an extension of HTTP and uses TLS/SSL to encrypt communication between a client and a server, ensuring data privacy and integrity.

Q. What does SQL stand for?
Structured Query Language
Sequential Query Language
Simple Query Language
Standard Query Language

Explanation:

SQL stands for Structured Query Language. It is the standard language for relational database management systems and is used for querying, inserting, updating, and deleting data.

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