Unlike staff agencies, line agencies
a. serve in a support capacity by offering advice.
b. are directly responsible for administering programs.
c. advise private programs of public interest.
d. primarily assist in the overall management of the executive branch.

Unlike staff agencies, line agencies are directly responsible for administering programs. The correct option among all the options that are given in the question is option "b". Line agencies are actually those departments within any organisation that focuses on the primary function and works of the organization.