The correct answer is A. pct_change.
The percent change is a measure of the relative change in a quantity between two points in time. It is calculated by dividing the difference between the two quantities by the initial quantity and multiplying by 100%.
The formula for calculating the percent change is:
Percent change = (new value – old value) / old value * 100%
For example, if the value of a stock is $100 today and $120 tomorrow, the percent change in the value of the stock is:
Percent change = (120 – 100) / 100 * 100% = 20%
The percent change can be used to compare the values of two quantities over time, to track the performance of an investment, or to identify trends.
The other options are not correct because they are not formulas for calculating the percent change.