Answer:
The wavelength of wave is 7.5 meter.
Given:
Speed of wave = 1500 
Frequency of wave = 200 Hz
To find:
Wavelength of wave = ?
Formula used:
Where 
= wavelength of the wave
v = speed of wave
n = frequency of wave
Solution:
Wavelength of wave is given by,
Where = wavelength of the wave
v = speed of wave
n = frequency of wave
= 7.5 m
The wavelength of wave is 7.5 meter.
R1 + R4 = 1430 + 1350 = 2780 = R14 series combination of R1 & R4
R2 + R5 = 1350 + 1150 = 2500 = R25
The circuit has been reduced to 3 resistors in parallel
R314 = 2780 * 1100 / (2780 + 1100) = 788 this is the resistance of the parallel combination of R14 and R3
R31425 = 2500 * 788 / (2500 + 788) = 599 which is the equivalent of the circuit - you can also use the formula for 3 resistors in parallel but this seems simpler
D is the correct answer!!
