A number x is selected at random from the interval [4,20]. The probability density function for x is given by the following function. Find the probability that a number selected is in the subinterval [6,15]. 1 f(x) = for 4x20. 16' How is the probability that a number selected is in the subinterval [6,15] calculated? 1 OA. Integrate 16 twice, then evaluate the integral over the limits 6 and 15. 1 OB. Evaluate over the limits 6 and 15, then add. 16 1 OC. Evaluate over the limits 6 and 15, then subtract. 16 1 OD. Integrate then evaluate the integral over the limits 6 and 15. 16 The probability is