Another question about relativity/light speed (harder)?

It's not that B's frame of reference is preferred: it's that he has one.

Twin A has TWO frames of reference: one for the outbound journey and one for the inbound journey. Special Relativity still works in each of them, but when he is at the turnaround point, those two frames strongly disagree on what moment of Earth history is simultaneous with his own--- what point of Earth history is going on "now." So when he switches frames, the concept of "now-on-Earth" changes.

Ja, what they said. Both can consider themselves stationary and the other twin moving, and both will see the other aging slowly because of that. BUT at some point A has to turn around and come back, so he changes reference frames and as he does that he sees B age very rapidly.

The twin that experiences an acceleration has not maintained an inertial reference frame.

Likewise, A experiences acceleration as he leaves earth and accelerates to the speed of light, and again as he slows back down to land. A begins at B's reference frame, changes to the outgoing frame, then to the incoming frame, then back to the original frame. B is in a single frame the entire time.

Symmetry is broken when one twin accelerates back toward the other. In order to bring the twins back to the same place and same reference frame, one or both needs to accelerate back toward the other. Acceleration causes a time dilation.

Twin A sees twin B flying by at close to the speed of light and notices that B is aging very slowly. B sees the same thing with respect to A: B sees A flying by and sees A aging very slowly. But to verify his observation, B turns on his thrusters and accelerates toward A. In doing that, B's clock slows and suddenly B sees A aging rapidly. By the time B rejoins his twin, they have aged the SAME except for the effects of acceleration, which were, perhaps, non-symmetric.

Your first paragraph is NOT the twin paradox. The second paragraph is. Both twins can't be right. However, there is a preferred frame, because one twin undergoes acceleration and the other doesn't. When acceleration is taken into account (using General Relativity), then there is no question as to which twin is older.

In addition to the twins in the problem, you also have "the silent witness" who is observing the change.

"Twin A gets into the space ship and takes off" implies that twin B and the observer remain relatively stationary.

If you reword the problem and say "You and twin A get into a space ship..."

You will be reporting your observations i.e.; "Twin B gets older."