Concept:Each letter is replaced by its alphabetical position, and the positions are written together.Explanation:For ROUTE:R=18, O=15, U=21, T=20, E=5.Concatenating gives 181521205.For COMPUTER:C=3, O=15, M=13, P=16, U=21, T=20, E=5, R=18.Concatenating gives 31513162120518.Answer:31513162120518 (Option D).