27. Sound is heard better in far areas during night time than during day time. Thus, open field concerts are often held during nighttime. Which of the following is the reason for this phenomenon?
a. The surrounding air at night brings about reverberations,
b. Sound bends toward the cooler region that gives more audible music at night. c. Sound waves are refracted from the cooler air above towards the hotter Earth's surface.
d. The cold air creates a booming sound during nighttime resulting to the fullness and depth of sound​