A Flashlight Bulb Typically Has a Small Metallic Button at One

A flashlight bulb typically has a small metallic button at one end, and this button is surrounded by ceramic material. The chief purpose of the ceramic material is to

A) provide a conducting path to the filament.
B) shut the filament off if the current gets too high.
C) provide extra mass at the bottom of the bulb.
D) insulate the metal button from the other contact point.