We Want to Know the Mean Winning Score at the US

Multiple Choice

We want to know the mean winning score at the US Open golf championship. An internet search
Gives us all the scores for the history of that tournament, and we create a 95% confidence interval
Based on a t-distribution. This procedure was not appropriate. Why?

A) The population standard deviation is known, so we should have used a z-model.
B) The entire population of scores was gathered so there is no reason to do inference.
C) In big golf tournaments the players are not randomly selected.
D) The recent record-setting score is probably an outlier.
E) Since these are the best players in the world, the scores are probably skewed.