Answer
(d) the mechanical energy is not conserved.
Work Step by Step
When a non-conservative force acts on an object, the mechanical energy is not conserved.
Mechanical energy is only conserved when conservative force act upon the object.
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.