The pressure at A, B, and C are the same.
The pressure in the water in the jug above the outside water surface is below your ambient air pressure. If you had a long pipe instead of a jug and you kept pulling it out of the water, eventually the pressure at the top of the pipe would reach 0 and the water column would stay in place even if more pipe was raised. There would be a near vacuum in the pipe above the water (it would be at the vapor pressure of the water at whatever temperature it was at the top of the column).
Think of this another way. If the pressure at B were higher than at A and C, then the water at B would flow to A and C. Since the water would be still if you waited for the waves to die down, all the water at the same height is at the same pressure.