Which table shows a probability distribution?

A) X- 0 1  2  3
    P-    0.3  0.1  0.2  0.2

B) X- 0 1  2  3
    P-    0.2  0.5  0.3  0.1  

C) X- 0 1  2  3
    P-    -0.3  0.6  0.5  0.2  

D) X- 0 1  2  3
    P-    0.3  0.2  0.1  0.4


its kinda difficult to upload a picture atm but i hope its understandable:)