For this chain-of-thought reasoning and answer, what was the question?
This is an alternating addition and subtraction series. In the first pattern, 10 is subtracted from each number to arrive at the next. In the second, 5 is added to each number to arrive at the next.
 A: (A)
user
Q: Look at this series: 80, 10, 70, 15, 60, ... What number should come next?
Options:
(A) 20
(B) 23
(C) 25
(D) 30
(E) 35
assistant