To test computer security and conduct encryption research, Tech Solutions Inc. circumvents the encryption software and other technological antipiracy protection of United Business Corporation$$s software. Under the Digital Millennium Copyright Act, this is

a$.$ prohibited but not a violation of copyright law.

b$.$ a violation of copyright law.

c$.$ permitted for reconsideration every three years.

d$.$ a $$fair use$$ exception to the provisions of the act.