Translation:How many hours do you spend on the computer every day?
You don't need 'the' in front of 'computer' in the English part of the world I come from (Australia). Everyone says "How many hours do you spend on computer every day?" No 'the' required. But of course marked wrong.
Coming back here after some months, and it still hasn't been added to the possible answers.
I think this comment in a completely different thread makes a good point.
The developers of the course are expected to [use] grammatical English sentences, and only the sentences they write are accepted. If you start accepting ungrammatical sentences then the possibilities become endless.