When a beam of white light is passed through Sodium vapours and then through a Spectrometer. Spectrum so obtained has two dark lines Present in the yellow region. This spectrum is called

 

The white bean absorbs sodium when it is passed through sodium vapours, and when it is then run through a spectrometer, it produces black fringes. Additionally, sodium vapours utilise sodium in an excited state to create light with a wavelength close to 589 nm.
Let's start by defining what white light hitting means. The statement that makes it clear. A sodium vapour is passed through by the white light. As is the case, sodium vapour lamps operate on a certain premise. Lightly efficient electrical spark of light when low pressure exists. However, yellow light can only be used for outdoor illumination. like as the often used street 1 am he. There, the sodium is efficiently absorbed by the light beam, which produces light.

Similar to that, in this instance, white light was used to detect sodium from its vapours, and through the spectrometer spectrum, 2 black lines were acquired in the yellow area, as we know the wavelength of the lamp was close to 589 nm.
As a result, sodium is absorbed here, producing a spectrum of sodium absorption.

Hence, the correct answer is option C.