Law enforcement investigations of cybercrime

are made difficult by $($select all that apply$)$:

A$)$private companies who are reluctant to share data with investigators as it may show criminal behavior of company customers $.$

B$)$ the crimes are often single occurrences therefore making it difficult to track evidence over a period of time.

C$)$ wrongdoers who may be in other jurisdictions unreachable by law enforcement.

D$)$ none of the above