Facilitated diffusion is the process through which solutes move across the membrane with the help of channel proteins, there is no required energy as occurs in active transport as the solute moves towards a lower concentration gradient. Taking this into consideration we can analyze each available option.
A) A substance was moving from a region of low concentration into a region of higher concentration. This is not correct as this is active transport.
B) Substances were moving against the diffusion gradient. This is not correct as is the same case as option A.
C) A substance was slowing as it moved down its concentration gradient. This must be approached carefully as in facilitated diffusion solutes move towards their gradient, however not necessarily the process is slower.
D) ATP was being rapidly consumed as the substance moved. This is not correct as energy is required in active transport
E) A substance was diffusing much faster than the physical condition indicated it should. This is correct as channel proteins and other transport proteins enhance the process of diffusion, so we can expect a higher rate.