Final answer:
The domain of the sequence An is all natural numbers. Hence the correct answer is option B
Step-by-step explanation:
The domain of a sequence represents the set of all valid inputs or values that the sequence can take. In this case, the sequence is represented by An. The sequence An is typically defined for all natural numbers. This means that the domain of the sequence is all natural numbers. We can write the domain of the sequence An as D = {1, 2, 3, ...}.
Hence the correct answer is option B