Option 1: The concept that light travels in a straight path is wrong.

This option is incorrect. The statement that optical fibres allow light to pass through even when bent does not necessarily mean that the concept of light traveling in a straight path is wrong. Rather, it indicates that light can still propagate through optical fibres despite being bent.

Option 2: Light can flow through the optical fibres.

This option is partially correct. The statement in the question suggests that light can indeed pass through optical fibres, but it does not provide a complete explanation of why this is possible.

Option 3: Light can travel through the fibres because of their ductility.

This option is incorrect. While ductility may be a property of certain materials used in optical fibres, it is not the primary reason why light can travel through them when bent.

Option 4: Light can travel through the fibres due to multiple total internal reflections.

This option is the correct answer. When light enters an optical fibre, it undergoes total internal reflection at the boundary between the core and the cladding of the fibre. This process allows the light to travel through the fibre by bouncing off the walls through multiple reflections. Even when the fibre is bent, these internal reflections still occur, enabling