Which tool is commonly used to sharpen a pencil?

Correct answer: Sharpener

A pencil sharpener is designed to remove a controlled layer of wood and expose a usable graphite point. That makes option A correct. A brush applies or moves paint, a compass helps draw circles or measure arcs, and a sponge may absorb or spread material; none is the ordinary tool for safely forming a pencil point. A sharp point also supports cleaner, more controlled marks.