Exam 300-815 topic 1 question 140 discussion

If B. is 831[0-10] and that is not typo, only have 2 numbers, so the next correct one will be the C. regardless the numbers are 100.

The range [0-10] is invalid, which makes B incorrect. C is the answer because if there are 100 DNs available, then there are 10 DNs available. The question only states the customer requires 10 DNs, not that the configuration must be exactly for 10 available DNs. So C satisfies both requirements of starting with 8 and providing a set of 10 DNs to park calls.

[0-10] means that for that specific dialed digit, in the sequence, only 0,1 and 0 will match. [0-9] is how you would match 10 digits. Example 8X or 8[0-9]. C is the only viable answer unless as stated previously, B would be correct if [0-9] was used.

B is the best answer assuming they meant [0-9] as [0-10] is not valid

I don't see a correct answer. [0-10] is not a valid range. If this was 831[0-9], then B would be correct. If there is a typo in the question and customer requires a set of 100 DNs (as opposed to 10), then the answer should be C.