In a certain code language, '134' means 'good and tasty'; '478' means 'see good pictures' and '729' means 'pictures are faint'. Which of the following digits stands for 'see'?

Justification: 

In the first and second statements, the common code digit is '4' and the common word is 'good'.

So, '4' stands for 'good'.
In the second and third statements, the  common code digit is '7' and the common word is 'pictures'.
So, '7' means 'pictures'.
Thus, in the second statements, '8' means 'see'.