Select the option that is related to the fifth number in the same way as the second number is related to the first number and the fourth number is related to the third number.

7 : 345 :: 5 : 127 :: 6 : ?

218

Logic is :

(1st number )³ + 2  = 2nd number

7 : 345

7³ + 2  =  343 + 2 = 345

5 : 127

5³ + 2  =  125 + 2 = 127

Similarly,

6 : ?

6³ + 2  =  216 + 2 = 218

218 is correct answer .