ABCD is parallelogram, consider the adjoining figure, The measure of ∠CBD is

60°
70°
50°
None of these

∠ A = ∠ C = 60° (Opposite angle of parallelogram)
In triangle BCD
∠ BDC + ∠ C + ∠ DBC = 180°
70° + 60° + ∠ DBC = 180°
∠ DBC = 50°