People in the Stock Market Refer to a Measure Called

People in the stock market refer to a measure called the "standard deviation," although it is calculated somewhat differently from the one discussed here. It is a good guess that this measure refers to

A) the riskiness of the stock.
B) the value of the stock.
C) how much the stock price is likely to fluctuate.
D) how much money you are likely to earn from buying that stock.