3. Let [3,, : n a 0} be a simple random walk which moves to the right with probability p at each step. and Suppose that So = 0. Write X n = S; Sn_1. (a) Show that {Sn = 0 i.o.} is not a tail event of the sequence {X J.,}. (b) Show that ms" = 01.0.) = 0 if p at