In figure , assuming the diodes to be ideal ,
A. `D_1` is forward biased and `D_2` is reverse biased and hence current flows from A to B.
B. `D_2` is forward biased and `D_1` is reverse biased and hence no current flows from B to A and vice versa.
C. `D_1 and D_2` are both forward biased and hence current flows from A to B.
D. `D_1 and D_2` are both reverse biased and hence no current flows from A to B and vice versa