Assume you have a pandas DataFrame defined as "df". If you wanted to access the names of the columns, you would run which line of code? columns(df) df.columns . df.column_names) df.columns() Assume you have a set of monthly pricing data defined as "x" and you load in the pandas library as pd. Which pandas built-in function allows you to calculate the 12 month rolling average price? pd.rollinglx, 365) . pd.rolling mean(x, 12) pd.rolling(x, 12) pd.rolling_mean(x, 365)