Final answer:
To predict a small gap size in speech, characteristics such as a fast rate and increased pitch are likely indicators because they correspond with the constraints that a smaller physical space would impose on sound resonance and speech patterns. The correct answer is A. Fast rate and increased pitch.
Step-by-step explanation:
The characteristics of speech to predict a small gap size would likely be fast rate and increased pitch. A fast rate of speaking can indicate a narrowed space, as it suggests a speaker is trying to fit words into a shorter timeframe, perhaps due to a limitation of space.
Additionally, an increased pitch can suggest an attempt to make sounds more acute, which corresponds with less physical space for sound resonance. Therefore, option A, which states a fast rate and increased pitch, would be associated with a small gap size.