There are very many combinations that will work. A bipolar stepper has 2 coils. Swapping the coils, or reversing the polarity of a coil, will simply cause the stepper to rotate in the opposite direction.
On RAMPS, one coil should connect to 1A and 1B, whereas the other coil should connect to 2A and 2B.
On the stepper, one coil is A+ and A-, the other coil is B+ and B-.
A possible wiring is A+ to 1A, A- to 1B and B+ to 2A and B- to 2B, but there are 15 other possibilities. The only "wrong" way is one that connects a coil of the stepper to two different coil outputs on the RAMPS (so connecting, for instance, A+ to 1A and A- to 2A wouldn't work).