Cynthia is reporting standardized test scores to parents of her students. She knows that on the test she gave the mean as an 80 and the standard deviation of 6. If her student Sharona received a Tscore of 40, which of the following can we accurately conclude regarding Sharona's performance?

Group of answer choices

a. Her performance was less than average.

b. She had a raw score greater than 80.

c. Her stanine score was an 8.

d. She had a positive z score.