A technician is working on a Windows 10 PC that has unwanted applications starting on...

 Task Manager is the best tool to use to disable applications on startup in Windows 10. Task Manager is a built-in utility that shows the current processes, performance, and users on a system. It also has a Startup tab that lists the applications that run on boot and their impact on the system. The technician can use Task Manager to disable or enable any application on startup by right-clicking on it and selecting the appropriate option. System Configuration, Performance Monitor, and Group Policy Editor are other tools that can be used to manage system settings, but they are not as simple or convenient as Task Manager for this task. References:

Official CompTIA learning resources CompTIA A+ Core 1 and Core 2, page 13

CompTIA A+ Complete Study Guide: Core 1 Exam 220-1101 and Core 2 Exam …, page 103