The following two-factor authentication (2FA) methods can be used to secure a GitHub account:
A . Authenticator app: You can use an authenticator app (like Google Authenticator or Authy) to generate time-based one-time passwords (TOTP) for logging in.
C . GitHub mobile: The GitHub mobile app can also be used to receive 2FA codes, adding convenience for users who prefer to manage everything from their mobile devices.
D . Security keys: Physical security keys (such as YubiKeys) can be used as a strong form of 2FA, requiring physical access to the key to authenticate.
Security questions and Single sign-on (SSO) are not considered 2FA methods in the context of GitHub account security.

In GitHub, labels are used to categorize issues and pull requests, and certain default labels are provided to help manage tasks:
Help Wanted Label:
Option C is correct. The "Help wanted" label is used to indicate that the maintainer of the repository needs assistance on a particular issue or pull request. This label helps in attracting contributors who might be interested in helping with specific tasks.
Other Options:
Option A ("Enhancement") is incorrect because it indicates a request for a new feature or improvement rather than a call for help.
Option B ("Question") is incorrect because it is used to flag issues or pull requests that seek clarification or additional information, not necessarily requiring assistance.
Option D ("Documentation") is incorrect because it labels issues or PRs related to documentation, not for seeking help.
Reference:
GitHub Docs: Using Labels

Pull requests are created to propose changes from one branch to another. These branches must be different; otherwise, there would be no changes to propose. Typically, pull requests are made from a feature or topic branch to a main branch (such as main or master), allowing for code review and integration before the changes are merged.

On GitHub, certain actions automatically subscribe you to conversations so that you receive notifications about further activity in that thread.
Opening a Pull Request or Issue:
Option C is correct because when you open a pull request or issue, you are automatically subscribed to the conversation and will receive notifications for any updates.
Commenting on a Thread:
Option D is correct because commenting on an issue or pull request automatically subscribes you to that thread, ensuring you are notified of further comments or changes.
Being Assigned to an Issue or Pull Request:
Option E is correct because when you are assigned to an issue or pull request, you are automatically subscribed to notifications related to it.
Incorrect Options:
Option A is incorrect because pushing a commit to the default branch does not automatically subscribe you to conversations.
Option B is incorrect because being added as a repo admin does not automatically subscribe you to specific conversations unless you engage with them.
Reference:
GitHub Docs: Subscribing to Notifications

The "Pinned Repositories" section of a GitHub user profile displays repositories that were personally selected to be highlighted by the user. Users can choose which repositories they want to feature prominently on their profile, regardless of recent activity, star count, or organizational ownership.