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.

When aggregate real personal income, industrial output, and the S&P 500 Index all increase in a given period, it is most accurate to conclude that a cyclical upturn is:
Option A:occurring.
Option B:about to end.
Option C:about to begin.

Answer: A