The lower the level of lighting is ... ?

[Anhminh1232002]

Hello, I should choose "A the level of lighting is" for the following sentence. Would you please tell me the correct option?

The lower ____ in a room, the more slowly our eyes focus.
A the level of lighting is
B light level is

Thank you.

[Beeesneees]

That's correct, Anhminh.

To use (B) you would need to add a definite article:
The lower the light level is in a room...
_________________
Cheers m' dears!

[Anhminh1232002]

what is the function of 'the' here?
Would you please tell me the usage of 'the'?
Let me write the sentence separately.
A The level of lighting in the room is low. Our eyes focus slowly.
B Light level in the room is low. Our eyes focus slowly.

I think: even without 'the', B is okay, too.
Thanks.

[Beeesneees]

'The' functions exactly as it does with any other noun.
In the first sentence, we are speaking about the specific light level. In the second we are speaking of light level more generally.

a) The level of light in the room is low - specifically, that light level.
b) Light level in the room is low - more general, acceptable in this context but not others.
c) The light level in the room is low. - specifically, the light level.

The water in that fountain tastes fresh - specifically, the water you get there.
Water in that fountain tastes fresh - more general. Acceptable in this context but not others.
_________________
Cheers m' dears!