Option B, singing in a tiled shower, is most likely to produce a loud echo. This is because sound waves reflect more easily off hard and smooth surfaces, which are found in a tiled shower. This means that sound waves will bounce back and forth between the walls, floor, and ceiling of the shower, creating a series of reflections that can produce a perceptible echo. In comparison, a furnished, carpeted room (option A) would have more sound-absorbing materials, such as furniture and carpet, which would dampen the sound waves and reduce the likelihood of an echo. Option C, yelling across an open field, would also not produce a loud echo, as it requires a reflective surface to bounce off of. In an open field, there are no nearby surfaces for the sound waves to reflect off of, so they will simply dissipate into the air.