According to the graph, what is the value of the constant in the equation below?

A.) 2.2
B.) 1.3
C.) 0.4
D.) 0.3

Determine the required value of the missing probability to make the distribution a discrete probability distribution. x p(x) 3 0.23 4 ? 5 0.51 6 0.08 p(4) = nothing  (type an integer or a decimal.)