IoT botnet construction tool "Mirai" was asked in Most famous Japanese information technology examinations

On October 21 2018, I received an information processing engineer exam administered by IPA.

May be that is most famous qualifying examination about software engineer in Japan.

I chose Information Security Specialist Examination(SC)

I found Mirai is asked in that exam.

here is the question

here is translation

Which of the following is malware Mirai's behavior?

A. It exploit vulnerabilities of Web servers that run on IoT devices etc. to spread infections, alter Web pages of Web servers, and perform DDos attacks on specific IP addresses at the date and time they were modified.

B. It exploiting Web server's vulnerability to insert illegal JavaScript into a company's Web page and direct the user who viewed the Web page to an unauthorized Web site

C. When the user erroneously and executes the malware execution file in the PC using the file sharing software, it uploads the information in the PC to the Web site on the Internet and makes it public to an unspecified number of people.

D. Try logging in to the telnet port by generating a random IP address, spreading infection to IoT devices using weak passwords at the time of factory shipment, etc. In accordance with the instructions from the C & C server, DDoS attack it dose.

Answer is D