The attenuation in optical fibre is mainly due to
(A) Absorption
(B) Scattering
(C) Neither absorption nor scattering
(D) Both (A) and (B)

Hint: In order to solve this question, we should know that an optical fibre is a very thin fibre cable through which we can send signals without much loss of the strength of the signal, Here we will first know the definition of each term given in option and then determine the correct reason of attenuation in optical fibre.

Complete step by step solution:
Whenever a signal is sent from one place to another, the strength of the signal gets reduced due to many factors affecting the signal strength and this reduction in strength of the signal is known as attenuation.

Now, when an electric signal is sent through an optical fibre then, some part of light energy gets absorbed by the glass of the optical fibre and light energy gets converted into another form most commonly as heat energy, Absorption is one of the causes of attenuation of signals in an optical fibre.

Also when light energy travels through an optical fibre, due to the presence of impurities in the manufacturing of the optical fibre light energy gets scattered in a sideways direction and hence reduces the strength of the signal and this becomes another reason for attenuation in an optical fibre. Therefore, Absorption and Scattering are the main reasons for attenuation in an optical fibre.

Hence, the correct answer is Option (D) i.e, Both (A) and (B)

Note: It should be remembered that, when an optical fibre is manufactured, sometimes its density of fibre is not the same throughout the fibre and hence due to this inhomogeneous structure of fibre light energy gets scattered and the strength of signals gets reduced.