Answer
$g$.
Work Step by Step
The mass of a jar of peanut butter is fairly light and the appropriate measuring unit is grams ($g$). That is, a jar of peanut butter contains 1200 $g$.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.