A Researcher Reports That "The Average Shopper in the Sample $\mu$

A researcher reports that "the average shopper in the sample (n = 12) purchased $65.00 worth of items ( $\mu$ = $65.00) during a busy shopping day." What mistake was made in this citation?

A) None; this citation is written appropriately.
B) The sample mean is written using the wrong notation.
C) The sample size is written using the wrong notation.
D) Both the sample mean is written using the wrong notation and the sample size is written using the wrong notation.