Aparticle executes a simple unrestricted random walk on a straight path, a step to the right of length 1 occurring with probability 1/3 and a step to the left of length 1 occurring with probability 2/3. initially the particle is at the origin. after the particle has been moving for some time, it is observed to be located at +8. if the particle returned to the origin, what is the probability that at some later time, it returns from there to the point +8? (a) 0.03911 (b) 0.00391 (c) 0.09311 (d) 0.39110