Study = 6 Hard = 7 Very = 8 Option 4 is correct. Alternate 678 ⇒ Study very hard ... (1) 347 ⇒ Hard work pays ... (2) 246 ⇒ Study & work ... (3) From (1) & (2), we can say that 7 is the code for hard. From (2) & (3), we get 4 is the code for work From (1) & (3) , we get 6 is the code for study ⇒ 8 is the code for very Option 4 is correct.