Question

correct the one error.
im sure its just a pigment of your imagination.
bro, when are you getting home?
i think i just heard a ghost.
dude! im sure its just a pigment of your imagination.

Explanation:

The error is a homophone mistake. "Pigment" refers to a coloring substance, while the correct word here is "figment", which means something imagined or made up, fitting the context of dismissing a ghost sighting as imaginary.

Answer:

Dude! I'm sure it's just a figment of your imagination.