$[20$ pts$.$ in total; $10$ pts$.$ and $10$ pts$.]$ Your state introduced a tax cut in the year $2017.$ You are interested in seeing whether this tax cut has led to increases in personal consumption within the state. You observe the following information:

A$.$ Your friend argues that the best estimate of the effect of the tax cut is an increase in consumption of $60$ units, but you think that the true effect is smaller because consumption was trending upward prior to the tax cut. What do you think is a better estimate?