For a discrete random variable XXX with PMF P(X=k)=13P(X=k) = \frac{1}{3}P(X=k)=31 for k∈{1,2,3}k \in \{1, 2, 3\}k∈{1,2,3}, what is E[X]E[X]E[X]?
111
222
333
1.51.51.5