The correct option is A Anything that allows all the light that falls on it to pass through, is transparent.
An object is said to be transparent when light passes through it without being reflected. If the light falling on an object is absorbed in it, the object will appear dark, if the light is reflected back then the object can be seen but if the light that falls on it is transmitted completely, that is, all the light is allowed to pass through it, then it will appear transparent.