Nurse Cecilia ended her home visit. She took her PHN bag and her black umbrella. The black umbrella is essential for home visits. The reason is:

A. Black is professional and fashionable as it matches the black PHN bag.
B. Black umbrella absorbs 90% of the sun's rays.
C. Black is visible to the color-blind dog and can be used to ward and scare him off.
D. Black does not dirty easily especially in the community where anything goes.