Final Answer:
The speed of a deep-water wave is proportional to its wavelength, so option a) Wavelength is the correct answer.
Step-by-step explanation:
The speed of a wave is determined by the formula: Speed (v) = Wavelength (λ) × Frequency (f). In deep water, where the water depth is significantly greater than the wavelength, the speed of the wave is primarily influenced by the wavelength. As wavelength increases, the speed of the wave also increases, and vice versa. Frequency and amplitude do not directly affect the speed of a deep-water wave. It's crucial to understand the relationships between these wave characteristics to comprehend the behavior of waves in different water depths.
Option A is answer.