We can use the Trigonometric ratio ‘Tan’ to get angle B (because you have all 3 lengths, you can use any ratio. I used tan because it didn’t make use of the decimal number).
TanB = opposite/adjacent TanB = 4/2 TanB = 2 B = Tan^-1(2) B = 63.43°
Your answer is D.
Please feel free to comment if you do not understand the use of ‘Tan^-1’
