A portfolio manager randomly samples 10 of the 100 sellside earnings estimates for a company. The sample mean was $3.35 and the standard deviation was $0.05. Subsequently, the portfolio manager finds a website that calculates the average for all 100 earnings estimates, with the average being $3.45. The difference between the sample mean of $3.35 and the population mean of $3.45 is most likely the result of:

Group of answer choices

A. sample selection bias.

B. data mining.

C. sampling error.