I believe there are two correct answers, and those answers are A and D
Answer: v = 880m/s
Explanation: The length of a string is related to the wavelength of sound passing through the string at the fundamental frequency is given as
L = λ/2 where L = length of string and λ = wavelength.
But L = 1m
1 = λ/2
λ = 2m.
But the frequency at fundamental is 440Hz and
V = fλ
Hence
v = 440 * 2
v = 880m/s
