2. Consider scanning literals for representing carbohydrates in chemistry. Such literals consist of one or more parts, each consisting of C, H, or 0, optionally followed by a decimal integer greater than 1 (it can greater than 9). You may use DO to mean decimal digits 0-9, D1 to mean 1-9, and D2 to mean 2-9. (This is a computer science question, not a chemistry question. In particular, this specification allows bogus chemical formulas such as H42.) a. Give a regular expression for these carbohydrate literals. You may use the iteration operators and + and ?. * b. Give a DFA that recognizes exactly these literals (no e edges). Don't forget to mark the start state and all accepting states. Make sure that you don't accept the empty string!