After they are used in the OTEC plant, the warm surface water and cold deep water (which is richer in inorganic nutrients) may be mixed together and discharged back into the ocean. In this process, an environmental concern is to not affect the local temperature profile so as to reduce impacts on sea life. If 22 °C and 5.5 °C water are mixed in equal volumes, at about what depth should the mixture be discharged so that the discharged mixture is at the same temperature as the surroundings?
A. 0 m
B. 100 m
C. 500 m
D. 1000 m