Out of those 2 answers I believe your answer would be B only because 81% of Americans in the us have a phone and 35% of people in the us check there phone more than 50 times per day
So, we know the sum of the first 17 terms is -170, thus S₁₇ = -170, and we also know the first term is 2, well

well, since the 17th term is that much, let's check what "d" is then anyway,
They are opposites of each other.
-13.2 + 8.1 = -5.1
13.2 - 8.1 = 5.1
Answer:
don't worry I'm on my way step bro ! where'd you get stuck ?! (;