Correct option is A
Given
P(X=3)=2P(X=1) and P(X=2)=0.3
Let
P(X=1)=k
=>P(X=3)=2k
Mean =0×P(0)+1×P(1)+2×P(2)+3×P(3)
1.3=k+2×0.3+6k
k=1/10=0.1
Now
P(X=0)+P(X=1)+P(X=2)+P(X=3)=1
P(X=0)+0.1+0.3+0.2=1
P(X=0) +0.6 =1
P(X=0)=0.4