If I understand the question correctly, the answer is ultimately: the aircraft will try to maintain attitude (including bank!).
The roots break down like this:
The AP as referred to on a 737 calssics is no more than a hydraulic system, that flips the controls but itself have no clue which direction or why.
Then you have the flight director system, which is the smart-ass that can compute the acceleration vector required. But still, it doesn't know where to and why either.
The FMC is the knowlegable one that is capable of assembling the flight trajectory.
(Yes, the pilot is the one who thinks he knows WHY)
Now, in full automation mode, the whole AFDS works like this>
The FMC has the uploaded track, profile and speeds, the FD constatnly recalculates how the airplane should behave to achieve so, and the AP works the ailerons and elevator+stab.trim.
Now this union at work may be broken at any point, i.e. you may disengage the FMC (LNAV &VNAV modes] from the FD and decide to tell the airplane where to go manually by using HDG SEL, ALT HLD, LVL CHG or V/S by setting the dials on MCP (glareshield panel). OR, you may want to disengage the autopilot and hand-fly the aeroplane on the FD'd bars - but it makes no real sense.
In conclusion, what the questions aims at is the CWS regime when the autopilot is engaged but knows not where to go. At that point it only tries to maintain given attitude. If you hand-fly to another attitude, it keeps it. Hence the name Control-Wheel-Steering. I was told this used to be the primary AP regime on -200s.
With no FD mode activated, the AP has no clue and engages in CWS, that's what happens.
G'day...
One more thing, I've been through the ATPL theory only 13 months ago, but what I recall is that the VERY EXACT wording used to be the enigma behind many questions. It seems to me that the answers do not match your question very well - or be it the other way around. Incidentally, I remember this too.
Cheers, FD.