[" 77.The potential energy "U],[" between two molecules as "],[" a function of the distance "],[" X between them has been "0],[" shown in the figure.The "],[" two molecules and "B" and are repelled when "X" lies "],[" (b) Attracted when "x" lies between "B" and "C" and are "],[" (b) Atracted when "X" lies between "A" and "B],[" (c) Attracted when they reach "B],[" (d) Repelled when they reach "B]