the relation that relates the speed of wave, frequency of wave and wavelength is given as
wavelength = 
the speed of wave in a medium remains constant. hence the wavelength is inversely related to the frequency of wave.
that means, as the frequency is increased, the wavelength decreases and vice versa.
hence the correct choice is
B decreases
Answer:
They would land at the same time
Explanation:
They would land at the same exact time.
As weird, impossible and unbelievable as it appears. When in a vacuum, every weight, body and material when released from the same height would land on the ground at the same time. This also means that like in the question, a feather and a ball would land at the same time. And just for illustrations as well, a feather and a car would land at the same time as well.
The image formed by a plane mirror is virtual, upright and the same size with the actual object. The upright image of an object in a plane mirror is can be found on the other side of the mirror which is why it is also virtual.