Microphobia is the fear of which of the following?

small things

The correct answer is Small things. Microphobia is the fear of small things. The word "micro" comes from the Greek word for "small". People with microphobia may avoid small objects altogether, or to experience severe anxiety when they are around small objects.

The other options are:

• Dirt: Hygophobia
• Germs: Germophobia
• Wind: Anemophobia