Algebra-1

To determine which sequence is arithmetic, check if the difference between consecutive terms is constant.

A. 

Differences:

1 - (-1) = 2

2 - 1 = 1

4 - 2 = 2

The differences are 2, 1, and 2, which are not consistent. This sequence is not arithmetic.

B. 

Ratios:

The ratios are consistently 2. This sequence is geometric, not arithmetic.

C.