Final answer:
To make a recording using a microphone on a computer, you should use the blue jack with a microphone icon.
Step-by-step explanation:
To identify the jack to use for plugging in a microphone into a computer, you should look for the blue jack with a microphone icon. This is typically the color and symbol used to represent the input for a microphone on a computer. The pink jack with a headphone icon is usually used for headphones, the green jack with a speaker icon is used for speakers, and the red jack with a line-in icon is used for external audio sources like a CD player or mixer.