One of the most important parts of making an espresso is to wipe down the steam wand after use. Why do we do this?

The bottom line is that the steam wands on the espresso machine need to be cleaned after EVERY use. ... The reason that you need to clean the steam wand after each use is that the milk dries on it very quickly after the frothing process and dried milk is incredibly hard to remove once caked on.

Ibelieve the answer  is b.