The correct answers to the question are 2,3,4 and 6 options respectively.
EXPLANATION:
Let us consider a wave which is moving with a speed v in a medium .
Let f and
is the frequency and wavelength of the wave.
The relation between frequency,wavelength and speed is given as -
speed = 
= 
The wavelength of the wave is calculated as -

Similarly frequency of the wave can be calculated as-

The option 1 is a wrong relation. So, we can not calculate the wavelength through this equation.
The option 2 is a right relation. By rearranging it, we can calculate the frequency of the wave.
The option 3 is a correct relation. So, we can calculate the wavelength through it.
The option 4 is also a correct relation. By rearranging it, we can calculate the wavelength.
The option 5 is a wrong relation.
The option 6 is also a right relation. By rearranging it, we can calculate the wavelength of the wave.