59. a walker travels along a one dimensional discrete lattice, labeled by points n, -n+ 1,...0, . n-1, n, by putting random left and/or right steps of length i

59. A walker travels along a one dimensional discrete lattice, labeled by points N, -N+ 1,...0, . N-1, N, by putting random left and/or right steps of length I with equal probability for every step. Suppose the random walker starts from the lattice position 0 and is found at the same lattice position after (i) 10 and (i) 7 step walks. The corresponding probabilities are respectively given by (A) 0.5, 0.5 (C) 0.25,0 (B) 0, 0.5 (D) 0.25, 0.25