Answer:
Option: d is the correct answer.
The domain for n is all the integers where n≥1.
Explanation:
We know that a geometric sequence also known as geometric progression in which each term is found by multiplying the preceding term by a constant factor.
That common factor is also known as a common ratio and is denoted by 'r'.
Now, the sequence is given as:

Hence, the nth term of the sequence is given by:
where n belongs to natural numbers.
Where a is the first term of the sequence i.e. when n=1
Hence, the domain for n is:
d. All integers where n ≥ 1