The correct answers are D. Restricting log-in times and E. Enabling a screen lock. These are the security measures that can be used to prevent the computers from being accessed by unsupervised contractors in the building.
* Restricting log-in times means setting a policy that allows users to log in only during certain hours, such as the regular working hours of the company. This will prevent unauthorized access by contractors who work at night1.
* Enabling a screen lock means setting a policy that requires users to enter a password or a PIN to unlock their screens after a period of inactivity. This will prevent unauthorized access by contractors who might try to use the computers when the users are away2.
1: CompTIA A+ Certification Exam: Core 2 Objectives, page 19, section 2.3. 2: CompTIA A+ Certification Exam: Core 2 Objectives, page 20, section 2.4.

The first step in troubleshooting is to check for any installed patches and roll them back one at a time until the issue is resolved. This can help to identify any patches that may be causing the issue and allow them to be removed.

In order to connect to a user's laptop via RDP, the technician should open port 3389 on the Windows firewall. This is because RDP uses port 3389 for communication12. The other options are not necessary or relevant for establishing an RDP connection.
* Confirming the user can ping the default gateway is not required for RDP, as it only tests the network connectivity between the user's laptop and the router. RDP works over the internet, so the technician should be able to ping the user's laptop directly using its IP address3.
* Changing the IP address on the user's laptop is not needed for RDP, as long as the IP address is valid and not conflicting with another device on the network. The user's laptop has a valid IP address of
* 192.168.0.45, which belongs to the same subnet as the gateway (192.168.0.1) and the subnet mask (255.255.255.0)4.
* Changing the subnet mask on the user's laptop is not required for RDP, as long as the subnet mask matches the network configuration. The user's laptop has a correct subnet mask of 255.255.255.0, which defines a network with 254 possible hosts4.
References:
1: [What is RDP and How Does It Work? - CompTIA] 2: CompTIA A+ Certification Exam Core 2 Objectives
- CompTIA 3: [Ping (networking utility) - Wikipedia] 4: [IP address - Wikipedia] : What is RDP and How Does It Work? - CompTIA : CompTIA A+ CertificationExamCore 2 Objectives - CompTIA : Ping (networking utility) - Wikipedia) : IP address - Wikipedia

The account access level the user will need to access advanced features and configuration settings for several applications while adhering to corporate policy requiring a least privilege environment is a standard account. This is because a standard account allows the user to access advanced features and configuration settings for several applications while adhering to corporate policy requiring a least privilege environment1.

Changing the network channel is the best solution to minimize the issue of employees and patients not being the only people on the Wi-Fi network5 References: 3. Sample CompTIA Security+ exam questions and answers. Retrieved from
https://www.techtarget.com/searchsecurity/quiz/Sample-CompTIA-Security-exam-questions-and-answers