How Has the Government Accountability Office's Role Changed

How has the Government Accountability Office's role changed?

A) It has acquired wide judicial and adjudication powers to deal with inter-agency disputes.
B) It has changed from a presidential-executive support agency to largely a congressional support agency.
C) It has been given broader powers over time to actually grant additional funds or take away funds directly from agencies.
D) It has its broad powers limited from general oversight down to keeping track of agency spending.
E) It has moved from a limited role of keeping track of agency spending to also monitoring whether the agency is implementing policies in the way Congress intended.