take a pencil and trace out current paths, you will see that both circuits are 100% identical. the only "difference" is that left and right branches are swapped, and one of them has elements drawn diagonally. all of this is purely cosmetic to make it more or less readable to humans - but electrically this makes no difference and they are identical.
Circuit A, top to bottom:
1) current flows from top, through R3 and R2 to bottom node, AND
2) current flows from top through R4 and R1 to bottom node
Circuit B, top to bottom:
1) current flows from top, through R3 and R2 to bottom node, AND
2) current flows from top through R4 and R1 to bottom node
I see identical descriptions... Circuits are same.
A. suppose we were not sure
B. there is nothing to indicate actual use of the circuit. in the end the whole circuit is just one glorified resistor - it can be used anywhere resistor is used or needed. there is nothing to say that it has to be modulating circuit, amplifier, oscillator, power supply or whatever
C. both circuits are identical and they are not bridge - until one more branch is added (in measuring bridge that would be galvanometer for example, in rectifier bridge that would be load, in H-bridge that would be motor etc.). besides what makes bridge a bridge is very specific circuit configuration - it does not matter what elements are used in different legs (could be anything: resistors, diodes, switches, transistors, inductors, capacitors, mix of anything)
D. impossible, because B and C are false. this means only option is A