Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

An analyst is examining the annual growth of the money supply for a country over the past 30 years. This country experienced a central bank policy shift 15 years ago, which altered the approach to the management of the money supply. The analyst estimated a model using the annual growth rate in the money supply regressed on the variable (SHIFT) that takes on a value of 0 before the policy shift and 1 after. She estimated the following:
| Coefficients | Standard Error | t-Stat. |
| Intercept | 5.767264 | 0.445229 | 12.95348 |
| SHIFT | -5.13912 | 0.629649 | -8.16188 |


Critical t-values, level of significance of 0.05:One-sided, left side: -1.701One-sided, right side: +1.701Two-sided: ±2.048
The variable SHIFT is best described as:
Option A:an indicator variable.
Option B:a dependent variable.
Option C:a continuous variable.

Answer: A