The correct option is D 7
In the first and second statement, the common word is 'hard' and the common code digit is '8'.
So, '8' means 'hard'.
In the first and third statements, the common word is 'study' and the common code digit is '6'.
So, '6' means 'study'.
Thus, in the first statement, '7' means 'very'.
Hence, the answer is (c).