One type of congressional committee is generally temporary in nature, made up of members of both houses$/$chambers of the Congress, and plays an investigatory or exploratory role $($but doesn't legislate$).$ An example of this type of committee would have been the Iran$-$Contra committee. This type of committee is referred to as a committee. If a temporary committee were set up in just one house$/$chamber of the Congress to play this investigatory role $($like the Senate Watergate committee or the House January $6$th committee$),$ this type of committee would be referred to as a committee.

A$)$ conference; joint.

B$)$ full; sub.

C$)$ joint; select or special.

D$)$ standing; conference.