Explanation
Starting with UiPath Studio version 2022.10, the default project type is Windows, which uses .NET 6 or .NET
5 with Windows support1. If a project contains dependencies that lack Windows compatibility, such as custom activities or libraries, they are marked as unresolved when the project is converted to Windows2. The developer needs to manually resolve them by finding compatible alternatives or updating the code3.
References:
Studio - Hardware and Software Requirements documentation, Project Compatibility section Getting error: No compatible version with windows projects forum post, Question by @RajeshT Uipath New Version Features - 2022.10.3 blog post, New Default Project Compatibility = Windows section

Explanation
The Type Into activity is used to enter text in a specified UI element, such as a text box. It has three input methods that can be selected from the properties panel: Default, Simulate, and Window Messages1. Each input method has different advantages and limitations, depending on the target application and the automation scenario2.
The Default input method uses the hardware driver to simulate the keystrokes, as if a human user is typing on the keyboard. It is the most reliable and compatible input method, but it requires the target application to be in focus and visible on the screen. It also supports sending special keys, such as Tab or Enter, using brackets [k(enter)] or [k(tab)].
The Simulate input method uses the technology of the target application to directly inject the text into the UI element. It does not rely on the hardware driver, so it can work in the background, even if the target application is hidden or minimized. It also supports sending special keys using brackets [k(enter)] or [k(tab)]. However, it may not be compatible with some applications or UI elements that do not support this method.
The Window Messages input method uses the Windows API to send messages directly to the target application. It can also work in the background, even if the target application is hidden or minimized. It does not support sending special keys using brackets [k(enter)] or [k(tab)], but it can send them using modifiers such as {ENTER} or {TAB}. However, it may not be compatible with some applications or UI elements that do not accept window messages.
Therefore, if a developer intends to enter text into an input field using a combination of a string and a hotkey, and the input action should take place within a hidden or minimized window, they can use either the Simulate or the Window Messages input method individually for the Type Into activity. They cannot use the Default input method, because it requires the target application to be in focus and visible on the screen. They also cannot use the Same as App/Browser input method, because it is not an option for the Type Into activity.
References:
Type Into - UiPath Documentation Portal.
What are different Input methods in UiPath - UiPath Community Forum.

Explanation
The InitAllApplications TestCase is used to test the initialization of all the applications that are required for the automation process1. The pre-requisite for running this TestCase is to invoke the InitAllSettings XAML file in the Given section of the TestCase2. The InitAllSettings file is responsible for reading the configuration data from the Config.xlsx file and storing it in a dictionary variable3. This data is then used by the InitAllApplications file to open and log in to the applications using the credentials and URLs from the dictionary variable4.

Explanation
The String.Join method takes two parameters: a separator and an array of strings. It returns a new string that concatenates the elements of the array using the separator. The correct syntax is String.Join(separator, array).
Therefore, option B is the correct answer.
References:
Automation Developer Associate Training course, Section 1: Data Manipulation, Lecture: Data Manipulation with Strings in Studio How to use Array of string forum post, Answer by @balupad14