Answer:
NO.
Explanation:
The given sequence is

The given sequence is not arithmetic, because there's no difference pattern. For example, the difference between 12.5 and 19 is -6.5, and the difference between 12.5 and -2 is 14.5, therefore it's not an arithmetic sequence, because they difference is not the same for all terms.
Therefore, the answer is the first choice NO.