Question

Which of these sentences is punctuated correctly?

A fire extinguisher, of course, is a good, idea.

Answer 1

This sentence is incorrectly punctuated:
A fire extinguisher, of course, is a good, idea.

The commas around "of course" are correct, but there does not need to be a comma after good. The sentence should read:
A fire extinguisher, of course, is a good idea.