@E-Li need your suggestion here 

Clients are reporting slowness when attempting to access a series of load-balanced APIs that do not require authentication. The servers that host the APIs are showing heavy CPU utilization. No alerts are found on the WAFs sitting in front of the APIs.

Which of the following should a security engineer recommend to BEST remedy the performance issues in a timely manner?

Options:

A Implement rate limiting on the API.
B Implement geoblocking on the WAF.
C Implement OAuth 2.0 on the API.
D Implement input validation on the API.

A company is repeatedly being breached by hackers who valid credentials. The company's Chief information Security Officer (CISO) has installed multiple controls for authenticating users, including biometric and token-based factors. Each successive control has increased overhead and complexity but has failed to stop further breaches. An external consultant is evaluating the process currently in place to support the authentication controls. Which of the following recommendation would MOST likely reduce the risk of unauthorized access?

A Implement strict three-factor authentication.

B Implement least privilege policies

C Switch to one-time or all user authorizations.

D Strengthen identify-proofing procedures

After a security incident, a network security engineer discovers that a portion of the company's sensitive external traffic has been redirected through a secondary ISP that is not normally used.

Which of the following would BEST secure the routes while allowing the network to function in the event of a single provider failure?

Options:

A Disable BGP and implement a single static route for each internal network.
B Implement a BGP route reflector.
C Implement an inbound BGP prefix list.
D Disable BGP and implement OSPF.   

A or B 

After a security incident, a network security engineer discovers that a portion of the company's sensitive external traffic has been redirected through a secondary ISP that is not normally used.

Which of the following would BEST secure the routes while allowing the network to function in the event of a single provider failure?

Options:

A Disable BGP and implement a single static route for each internal network.
B Implement a BGP route reflector.
C Implement an inbound BGP prefix list.
D Disable BGP and implement OSPF.