The “ultimate number” can be calculated in this way: add up the values of each digit until there is only one digit left. For example, 9901, 9+9+0+1= 19, 1+9= 10, 1+0=1, 1 is the “ultimate number” of 9901. How many two-digit numbers are there that have the same ultimate number as 50645?
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正确答案: C