on your lunch break, you walked down to the coffee shop on the corner. you open your laptop and connect to their wireless network. after a few minutes of surfing the internet, a pop-up is displayed on your screen. you close the pop-up, finish your lunch break, shut down the laptop, and put it back into your backpack. when you get back to the office, you take out the laptop and turn it on, but instead of your normal desktop background, you are greeted by a full-screen image with a padlock and a message stating you have to pay 0.1 btc to regain access to your personal files. what type of malware has infected your laptop?