How do the three subpoints in the following outline violate standard outlining form

A. The current status of our blood supply creates a bleak picture.
1. There is a serious depletion of blood bank supplies.
2. Potential donors have quit donating blood.
3. Contaminated blood.
a. The subpoints in the outline are not all grammatically parallel.
b. The subpoints in the outline follow correct indentation standards.
c. The subpoints in the outline are not logically divided.
d. Only Roman numerals should appear in outlines, not Arabic numbers.

a