Answer:
C. Leisurely
Step-by-step explanation:
Leisurely can mean that something is done in a gentle or relaxed manner, thus, it doesn't have a negative connotation.
On the other hand, slothful means inactivity; sluggish means that something lacks energy or is inactive; and lazy means that someone doesn't want to do anything at all.
All of these words are synonymous related to laziness, thereby, carrying a negative connotation.