The .bat file type would be used in the Windows Startup folder to automate copying a personal storage table (.pst) file to a network drive at log-in. A .bat file is a batch file that contains a series of commands that can be executed by the command interpreter. A .bat file can be used to perform various tasks, such as copying, moving, deleting, or renaming files or directories. A .bat file can be placed in the Windows Startup folder to run automatically when a user logs in to the system. A .bat file can use the copy command to copy a .pst file from a local drive to a network drive. A .pst file is a personal storage table file that contains email messages, contacts, calendars, and other data from Microsoft Outlook. A .pst file can be backed up to a network drive for security or recovery purposes. The .dll, .ps1, and .txt file types are not used in the Windows Startup folder to automate copying a .pst file to a network drive at log-in. A .dll file is a dynamic link library file that contains code or data that can be shared by multiple programs. A .dll file cannot be executed directly by the user or the system. A .ps1 file is a PowerShell script file that contains commands or expressions that can be executed by the PowerShell interpreter. A .ps1 file can also perform various tasks, such as copying files or directories, but it requires PowerShell to be installed and configured on the system. A .txt file is a plain text file that contains unformatted text that can be read by any text editor or word processor. A .txt file cannot contain commands or expressions that can be executed by the system. Reference:
Official CompTIA learning resources CompTIA A+ Core 1 and Core 2, page 18 CompTIA A+ Core 1 (220-1101) and Core 2 (220-1102) Cert Guide, page 459

Hash verification is a process that verifies the integrity of a file by comparing the hash value of the downloaded file to the hash value provided by the source1

When a user can access the local network (as evidenced by printing to network printers) but not the internet, the issue is often related to Domain Name System (DNS) resolution. DNS is responsible for translating domain names (like google.com) into IP addresses that computers use to communicate. If the DNS settings are incorrect or the DNS server is unreachable, the computer won't be able to find the IP addresses of websites and other internet resources.

The most likely cause of the user's issue of applications opening without being launched and browser redirects when trying to go to certain websites is malware. Malware is a general term that refers to any software or code that is malicious or harmful to a computer or system. Malware can perform various unwanted or unauthorized actions on a computer or system, such as opening applications, redirecting browsers, displaying ads, stealing data, encrypting files or damaging hardware. Malware can infect a computer or system through various means, such as email attachments, web downloads, removable media or network connections. Keylogger is a type of malware that records and transmits the keystrokes made by a user on a keyboard. Keylogger can be used to steal personal or sensitive information, such as passwords, credit card numbers or chat messages. Keylogger does not typically open applications or redirect browsers but only captures user inputs. Cryptominers are a type of malware that use the computing resources of a computer or system to mine cryptocurrency, such as Bitcoin or Ethereum. Cryptominers can degrade the performance and increase the power consumption of a computer or system. Cryptominers do not typically open applications or redirect browsers but only consume CPU or GPU cycles. Virus is a type of malware that infects and replicates itself on other files or programs on a computer or system.

AirDrop is a feature on Apple devices that allows users to wirelessly share files, photos, and videos with nearby Apple devices. If the MacBook is receiving unsolicited AirDrop requests, adjusting the AirDrop settings to allow sharing with contacts only or turning it off completely can help prevent these random pop-up requests.