z-score's

A distribution of test scores is not symmetric. Which of the following is the best estimate of the z-score of the third quartile?
a. 0.67
b. 0.75
c. 1.00
d. 1.41
e. this z-score cannot be estimated from the information given.

I think that the answer is e because they give very little information. I'm just not sure if I'm right.

1) If a z-score is appropriate, there can't be a WHOLE lot of skewness.
2) What is the bottom score of the 3rd quartile? Can you estimate the median?
3) How does one estimate the quartile? Top? Bottom? Middle? Something else?

I don't get it. What is your answer?