After returning from a conference, a user's laptop has been operating slower than normal and overheating, and the fans have been running constantly. During the ...

After returning from a conference, a user's laptop has been operating slower than normal and overheating, and the fans have been running constantly. During the diagnosis process, an unknown piece of hardware is found connected to the laptop's motherboard. Which of the following attack vectors was exploited to install the hardware?

A. Removable media B. Spear phishing C. Supply chain D. Direct access