Accreditation of laboratories that do forensic investigations is: a. always required
b. done voluntarily
c. done using independent nongovernmental agencies such as ASTM and ISO
d. done by a special government agency to insure uniformity of testing and results across all laboratories is never done since this
e. is expensive and does not improve the results obtained by the laboratory

a. always required

Explanation:

Accreditation of laboratories is a mandatory requirement for forensic science providers. To manage the quality of services provided by the forensic laboratories, Accreditation, Certification, and Interagency Working Group have found it necessary to make the accreditation of forensic laboratories mandatory.

This will instill confidence in the public and ensure that the services rendered by them are always accurate and up to standard.