The correct answer of the question is : 0.001 s.
CALCULATION:
As per the question, the speed of sound v = 330 m/s
The frequency of the sound f = 990 Hz.
Let the wavelength of the wave is \(\lambda\).
The wavelength of the wave is calculated as-
wavelength \(\lambda=\frac{speed}{frequency}\)
= \(\frac{330}{990}\ m\)
= 0.33 m.
Now we are asked to calculate the time period.
The time period of the wave is reciprocal of frequency.
Mathematically time period T = \(\frac{1}{f}\)
= \(\frac{1}{990}\ s\)
= 0.001 s.
As per the question, we need the period.
Hence, the period of the wave is 0.001 s.
