Of the following summaries, which are true with regards to Defense Support to Civil Authorities $($DSCA$)?$

a$)$ The four defining characteristics of DSCA are: I. State and Federal laws define how military forces support civil authorities; II$.$ Civil authorities are in charge, and military forces support them; III. Military forces depart when civil authorities are able to continue without military support; IV$.$ Military forces must document the costs of all direct and indirect support provided.

b$)$ The Posse Comitatus Act of $1878$ is the original statutory basis that limits domestic military involvement in state or local assistance without specific authority, request, and mission approval.

c$)$ Military support roles within DSCA may include: assisting with response to natural and manmade disasters; border security; counterterrorism efforts; wildfire response; critical infrastructure protection; human, animal, or crop disease response; CBRNE assistance $($chemical$,$ biological, radiological, nuclear, explosive$),$ among others.