Gregor, the mathematician, forms two numbers with the digits $$0$$, $$1$$, $$2$$, $$3$$, $$4$$, and $$5$$. Both numbers have three digits, and each digit is used only once. He adds these two numbers. What is the greatest sum Gregor can get? (adapted from 2012 Math Kangaroo Problem, Level 3 - 4, Question \#19) 
选项为:A:$$753$$  B:$$861$$  C:$$951$$  D:$$1086$$  E:$$1110$$  请回答其中一个选项.