Please help I have been stuck on these homework question for a long time!!

a)

Which of the following statements best describes the behavior of mechanical waves in fluid media?Mechanical waves cannot travel through fluid media. Gases that are the least dense are able to transmit mechanical waves more efficiently because of the free range of motion of the molecules. Liquids are less efficient at transmitting mechanical waves because they are denser and dampen the effects. Denser fluids such as liquids and compressed gases are more efficient at transmitting mechanical waves because the molecules are closer and transmit energy more easily.Scientists have found that the long slow moan produced by blue whales is almost consistently a B pitch at a frequency of 16.0 Hz. The wavelength of this note is 97.5 m. How long would it take for this sound from a blue whale to travel to a team of scientists that is tracking them from 12 km away