I think it's C, longer wave length.
Are you referring to the fact that water is a compound while hydrogen is an element? If I'm wrong just comment and clarify and I can edit it, I don't even know what kind of unit you're in. :)
Have you tried to look this up on Quizlet. I just had a similar question on one on my quizzes & the whole test was on Quizlet
English: Cardiovascular efficiency depends on a number of factors. One measure is called stroke volume, which is the volume of blood pumped per heartbeat. A fit individual has a larger stroke volume, which means a greater volume of oxygen is delivered to the body per heartbeat.
Spanish: La eficacia cardiovascular depende de una serie de factores. Una medida se denomina volumen sistólico, que es el volumen de sangre bombeada por latidos cardíacos. Un individuo en forma tiene un volumen de movimiento mayor, lo que significa que un mayor volumen de oxígeno es entregado al cuerpo por latidos cardíacos.
Answer:
The wavelength of the wave is 20 m.
Explanation:
Given that,
Amplitude = 10 cm
Radial frequency 
Bulk modulus = 40 MPa
Density = 1000 kg/m³
We need to calculate the velocity of the wave in the medium
Using formula of velocity

Put the value into the formula


We need to calculate the wavelength
Using formula of wavelength


Put the value into the formula


Hence, The wavelength of the wave is 20 m.